CVE-2024-50086 (GCVE-0-2024-50086)

Vulnerability from cvelistv5 – Published: 2024-10-29 00:50 – Updated: 2026-08-05 11:41
VLAI
Title
ksmbd: fix user-after-free from session log off
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix user-after-free from session log off There is racy issue between smb2 session log off and smb2 session setup. It will cause user-after-free from session log off. This add session_lock when setting SMB2_SESSION_EXPIRED and referece count to session struct not to free session while it is being used.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-04-25 14:30 UTC
CWE
Assigner
Linux CNA under the mitre root
CNA scorecard D 54/100 over 6618 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 0f62358ce85b2d4c949ef1b648be01b29cec667a (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < a9839c37fd813b432988f58a9d9dd59253d3eb2c (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 5511999e9615e4318e9142d23b29bd1597befc08 (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < ee371898b53a9b9b51c02d22a8c31bfb86d45f0d (git)
Affected: 0626e6641f6b467447c81dd7678a69c66f7746cf , < 7aa8804c0b67b3cb263a472d17f2cb50d7f1a930 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 5.15.171 , ≤ 5.15.* (semver)
Unaffected: 6.1.114 , ≤ 6.1.* (semver)
Unaffected: 6.6.58 , ≤ 6.6.* (semver)
Unaffected: 6.11.5 , ≤ 6.11.* (semver)
Unaffected: 6.12 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 7.8,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2024-50086",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-04-25T14:30:09.987767Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-416",
                "description": "CWE-416 Use After Free",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2025-04-25T14:36:34.763Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T22:25:18.791Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/mgmt/user_session.c",
            "fs/smb/server/mgmt/user_session.h",
            "fs/smb/server/server.c",
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0f62358ce85b2d4c949ef1b648be01b29cec667a",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "a9839c37fd813b432988f58a9d9dd59253d3eb2c",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "5511999e9615e4318e9142d23b29bd1597befc08",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "ee371898b53a9b9b51c02d22a8c31bfb86d45f0d",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            },
            {
              "lessThan": "7aa8804c0b67b3cb263a472d17f2cb50d7f1a930",
              "status": "affected",
              "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/mgmt/user_session.c",
            "fs/smb/server/mgmt/user_session.h",
            "fs/smb/server/server.c",
            "fs/smb/server/smb2pdu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.171",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.114",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.58",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.11.*",
              "status": "unaffected",
              "version": "6.11.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.12",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.171",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.114",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.58",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.11.5",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix user-after-free from session log off\n\nThere is racy issue between smb2 session log off and smb2 session setup.\nIt will cause user-after-free from session log off.\nThis add session_lock when setting SMB2_SESSION_EXPIRED and referece\ncount to session struct not to free session while it is being used."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - ksmbd is the in-kernel SMB server processing attacker-supplied SMB2 PDUs on TCP/445 (or RDMA), so the entire race is driven by remote network traffic. No local access to the target is required.\nAC:L - The attacker controls both sides of the race \u2014 one pipelined SMB2 request holds the raw `work-\u003esess` pointer while a second concurrently issued SMB2_SESSION_SETUP drives `ksmbd_expire_session()` into `kfree(sess)` \u2014 and each PDU is dispatched to a separate workqueue item, so the race can be replayed indefinitely and widened with compound/large requests.\nPR:N - No credentials are needed: `__session_create()` leaves a session `SMB2_SESSION_IN_PROGRESS` and `smb2_sess_setup()`\u0027s error path marks it `SMB2_SESSION_EXPIRED`, both of which `ksmbd_expire_session()` frees, while the concurrent work item still dereferences `work-\u003esess` in `smb3_preauth_hash_rsp()`/`set_sign_rsp()` after `ksmbd_conn_unlock()`. The logoff variant needs only an ordinary (including guest-mapped) SMB session.\nUI:N - The attacker triggers everything by sending SMB2 requests to the listening ksmbd server; no action by any local user or administrator is involved.\nS:U - The corruption and its consequences stay within the kernel\u0027s own security authority on the SMB server host, with no crossing of a VM, sandbox, or IOMMU boundary.\nC:H - After the free, `set_sign_rsp()` HMACs the response with `sess-\u003esmb3signingkey` read from reclaimed slab memory and returns the result to the attacker, and `sess-\u003efile_table`/`sess-\u003etree_conns` lookups on freed xarrays yield attacker-influenced pointers, enabling disclosure of arbitrary kernel memory.\nI:H - `smb3_preauth_hash_rsp()` writes a 64-byte SHA-512 result through the `Preauth_HashValue` pointer read out of the freed object, giving a controlled kernel write once the slab is sprayed; the freed `file_table`/`tree_conns`/`user` fields additionally allow type confusion and control-flow hijacking.\nA:H - Even without successful exploitation the use-after-free dereferences freed slab memory and corrupts the allocator, producing kernel oopses and panics that take down the SMB server host, and it can be retriggered at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:41:31.690Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0f62358ce85b2d4c949ef1b648be01b29cec667a"
        },
        {
          "url": "https://git.kernel.org/stable/c/a9839c37fd813b432988f58a9d9dd59253d3eb2c"
        },
        {
          "url": "https://git.kernel.org/stable/c/5511999e9615e4318e9142d23b29bd1597befc08"
        },
        {
          "url": "https://git.kernel.org/stable/c/ee371898b53a9b9b51c02d22a8c31bfb86d45f0d"
        },
        {
          "url": "https://git.kernel.org/stable/c/7aa8804c0b67b3cb263a472d17f2cb50d7f1a930"
        }
      ],
      "title": "ksmbd: fix user-after-free from session log off",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2024-50086",
    "datePublished": "2024-10-29T00:50:29.284Z",
    "dateReserved": "2024-10-21T19:36:19.942Z",
    "dateUpdated": "2026-08-05T11:41:31.690Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2024-50086",
      "date": "2026-10-10",
      "epss": "0.00477",
      "percentile": "0.3928"
    },
    "fkie_nvd": {
      "configurations": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "matchCriteriaId": "CCCFB10D-CB4C-4D7A-BACF-D4AE755765D9",
                  "versionEndExcluding": "6.1.114",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "matchCriteriaId": "6B9489BC-825E-4EEE-8D93-F93C801988C8",
                  "versionEndExcluding": "6.6.58",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "matchCriteriaId": "6E62D61A-F704-44DB-A311-17B7534DA7BC",
                  "versionEndExcluding": "6.11.5",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:*",
                  "matchCriteriaId": "7F361E1D-580F-4A2D-A509-7615F73167A1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:*",
                  "matchCriteriaId": "925478D0-3E3D-4E6F-ACD5-09F28D5DF82C",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:*",
                  "matchCriteriaId": "3C95E234-D335-4B6C-96BF-E2CEBD8654ED",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix user-after-free from session log off\n\nThere is racy issue between smb2 session log off and smb2 session setup.\nIt will cause user-after-free from session log off.\nThis add session_lock when setting SMB2_SESSION_EXPIRED and referece\ncount to session struct not to free session while it is being used."
        },
        {
          "lang": "es",
          "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ksmbd: se corrige el problema de user-after-free del cierre de sesi\u00f3n. Hay un problema de velocidad entre el cierre de sesi\u00f3n de smb2 y la configuraci\u00f3n de la sesi\u00f3n de smb2. Esto provocar\u00e1 que el user-after-free cierre la sesi\u00f3n. Esto agrega session_lock al configurar SMB2_SESSION_EXPIRED y hace referencia a count en la estructura de sesi\u00f3n para no liberar la sesi\u00f3n mientras se est\u00e1 utilizando."
        }
      ],
      "id": "CVE-2024-50086",
      "lastModified": "2024-11-08T16:15:46.247",
      "metrics": {
        "cvssMetricV31": [
          {
            "cvssData": {
              "attackComplexity": "HIGH",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 7.0,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            },
            "exploitabilityScore": 1.0,
            "impactScore": 5.9,
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      },
      "published": "2024-10-29T01:15:05.487",
      "references": [
        {
          "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "url": "https://git.kernel.org/stable/c/0f62358ce85b2d4c949ef1b648be01b29cec667a"
        },
        {
          "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "tags": [
            "Patch"
          ],
          "url": "https://git.kernel.org/stable/c/5511999e9615e4318e9142d23b29bd1597befc08"
        },
        {
          "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "tags": [
            "Patch"
          ],
          "url": "https://git.kernel.org/stable/c/7aa8804c0b67b3cb263a472d17f2cb50d7f1a930"
        },
        {
          "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "tags": [
            "Patch"
          ],
          "url": "https://git.kernel.org/stable/c/a9839c37fd813b432988f58a9d9dd59253d3eb2c"
        },
        {
          "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "tags": [
            "Patch"
          ],
          "url": "https://git.kernel.org/stable/c/ee371898b53a9b9b51c02d22a8c31bfb86d45f0d"
        }
      ],
      "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "vulnStatus": "Modified",
      "weaknesses": [
        {
          "description": [
            {
              "lang": "en",
              "value": "CWE-416"
            }
          ],
          "source": "nvd@nist.gov",
          "type": "Primary"
        }
      ]
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/smb/server/mgmt/user_session.c",
                  "fs/smb/server/mgmt/user_session.h",
                  "fs/smb/server/server.c",
                  "fs/smb/server/smb2pdu.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "0f62358ce85b2d4c949ef1b648be01b29cec667a",
                    "status": "affected",
                    "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "a9839c37fd813b432988f58a9d9dd59253d3eb2c",
                    "status": "affected",
                    "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "5511999e9615e4318e9142d23b29bd1597befc08",
                    "status": "affected",
                    "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "ee371898b53a9b9b51c02d22a8c31bfb86d45f0d",
                    "status": "affected",
                    "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "7aa8804c0b67b3cb263a472d17f2cb50d7f1a930",
                    "status": "affected",
                    "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "fs/smb/server/mgmt/user_session.c",
                  "fs/smb/server/mgmt/user_session.h",
                  "fs/smb/server/server.c",
                  "fs/smb/server/smb2pdu.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "5.15"
                  },
                  {
                    "lessThan": "5.15",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.15.*",
                    "status": "unaffected",
                    "version": "5.15.171",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.1.*",
                    "status": "unaffected",
                    "version": "6.1.114",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.58",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.11.*",
                    "status": "unaffected",
                    "version": "6.11.5",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "6.12",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "CCCFB10D-CB4C-4D7A-BACF-D4AE755765D9",
                    "versionEndExcluding": "6.1.114",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "6B9489BC-825E-4EEE-8D93-F93C801988C8",
                    "versionEndExcluding": "6.6.58",
                    "versionStartIncluding": "6.2",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "6E62D61A-F704-44DB-A311-17B7534DA7BC",
                    "versionEndExcluding": "6.11.5",
                    "versionStartIncluding": "6.7",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "7F361E1D-580F-4A2D-A509-7615F73167A1",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "925478D0-3E3D-4E6F-ACD5-09F28D5DF82C",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:*",
                    "matchCriteriaId": "3C95E234-D335-4B6C-96BF-E2CEBD8654ED",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix user-after-free from session log off\n\nThere is racy issue between smb2 session log off and smb2 session setup.\nIt will cause user-after-free from session log off.\nThis add session_lock when setting SMB2_SESSION_EXPIRED and referece\ncount to session struct not to free session while it is being used."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ksmbd: se corrige el problema de user-after-free del cierre de sesi\u00f3n. Hay un problema de velocidad entre el cierre de sesi\u00f3n de smb2 y la configuraci\u00f3n de la sesi\u00f3n de smb2. Esto provocar\u00e1 que el user-after-free cierre la sesi\u00f3n. Esto agrega session_lock al configurar SMB2_SESSION_EXPIRED y hace referencia a count en la estructura de sesi\u00f3n para no liberar la sesi\u00f3n mientras se est\u00e1 utilizando."
          }
        ],
        "id": "CVE-2024-50086",
        "lastModified": "2026-08-04T11:21:16.980",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            },
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.0,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.0,
              "impactScore": 5.9,
              "source": "nvd@nist.gov",
              "type": "Primary"
            },
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2024-50086",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2025-04-25T14:30:09.987767Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2024-10-29T01:15:05.487",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/0f62358ce85b2d4c949ef1b648be01b29cec667a"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/5511999e9615e4318e9142d23b29bd1597befc08"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/7aa8804c0b67b3cb263a472d17f2cb50d7f1a930"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/a9839c37fd813b432988f58a9d9dd59253d3eb2c"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/ee371898b53a9b9b51c02d22a8c31bfb86d45f0d"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-416"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          },
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-416"
              }
            ],
            "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-13T18:32:56+00:00",
      "cve": "CVE-2024-50086",
      "id": "CVE-2024-50086",
      "initial_release_date": "2024-10-29T00:00:00+00:00",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ksmbd: fix user-after-free from session log off",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2024/cve-2024-50086.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-10-11T00:06:21Z",
      "cve": "CVE-2024-50086",
      "id": "CVE-2024-50086",
      "initial_release_date": "2024-10-29T04:15:38Z",
      "product_status:known_not_affected": "498",
      "product_status:recommended": "6",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2024-50086",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2024-50086.json",
      "version": "25"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2025-11-03T22:25:18.791Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "metrics": [
              {
                "cvssV3_1": {
                  "attackComplexity": "LOW",
                  "attackVector": "LOCAL",
                  "availabilityImpact": "HIGH",
                  "baseScore": 7.8,
                  "baseSeverity": "HIGH",
                  "confidentialityImpact": "HIGH",
                  "integrityImpact": "HIGH",
                  "privilegesRequired": "LOW",
                  "scope": "UNCHANGED",
                  "userInteraction": "NONE",
                  "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                  "version": "3.1"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2024-50086",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "total"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2025-04-25T14:30:09.987767Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "cweId": "CWE-416",
                    "description": "CWE-416 Use After Free",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2025-04-25T14:30:11.300Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "fs/smb/server/mgmt/user_session.c",
                "fs/smb/server/mgmt/user_session.h",
                "fs/smb/server/server.c",
                "fs/smb/server/smb2pdu.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "0f62358ce85b2d4c949ef1b648be01b29cec667a",
                  "status": "affected",
                  "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                  "versionType": "git"
                },
                {
                  "lessThan": "a9839c37fd813b432988f58a9d9dd59253d3eb2c",
                  "status": "affected",
                  "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                  "versionType": "git"
                },
                {
                  "lessThan": "5511999e9615e4318e9142d23b29bd1597befc08",
                  "status": "affected",
                  "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                  "versionType": "git"
                },
                {
                  "lessThan": "ee371898b53a9b9b51c02d22a8c31bfb86d45f0d",
                  "status": "affected",
                  "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                  "versionType": "git"
                },
                {
                  "lessThan": "7aa8804c0b67b3cb263a472d17f2cb50d7f1a930",
                  "status": "affected",
                  "version": "0626e6641f6b467447c81dd7678a69c66f7746cf",
                  "versionType": "git"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "fs/smb/server/mgmt/user_session.c",
                "fs/smb/server/mgmt/user_session.h",
                "fs/smb/server/server.c",
                "fs/smb/server/smb2pdu.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "5.15"
                },
                {
                  "lessThan": "5.15",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.15.*",
                  "status": "unaffected",
                  "version": "5.15.171",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.1.*",
                  "status": "unaffected",
                  "version": "6.1.114",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.6.*",
                  "status": "unaffected",
                  "version": "6.6.58",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "6.11.*",
                  "status": "unaffected",
                  "version": "6.11.5",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "6.12",
                  "versionType": "original_commit_for_fix"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.15.171",
                      "versionStartIncluding": "5.15",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.1.114",
                      "versionStartIncluding": "5.15",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.6.58",
                      "versionStartIncluding": "5.15",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.11.5",
                      "versionStartIncluding": "5.15",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.12",
                      "versionStartIncluding": "5.15",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix user-after-free from session log off\n\nThere is racy issue between smb2 session log off and smb2 session setup.\nIt will cause user-after-free from session log off.\nThis add session_lock when setting SMB2_SESSION_EXPIRED and referece\ncount to session struct not to free session while it is being used."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "scenarios": [
                {
                  "lang": "en",
                  "value": "AV:N - ksmbd is the in-kernel SMB server processing attacker-supplied SMB2 PDUs on TCP/445 (or RDMA), so the entire race is driven by remote network traffic. No local access to the target is required.\nAC:L - The attacker controls both sides of the race \u2014 one pipelined SMB2 request holds the raw `work-\u003esess` pointer while a second concurrently issued SMB2_SESSION_SETUP drives `ksmbd_expire_session()` into `kfree(sess)` \u2014 and each PDU is dispatched to a separate workqueue item, so the race can be replayed indefinitely and widened with compound/large requests.\nPR:N - No credentials are needed: `__session_create()` leaves a session `SMB2_SESSION_IN_PROGRESS` and `smb2_sess_setup()`\u0027s error path marks it `SMB2_SESSION_EXPIRED`, both of which `ksmbd_expire_session()` frees, while the concurrent work item still dereferences `work-\u003esess` in `smb3_preauth_hash_rsp()`/`set_sign_rsp()` after `ksmbd_conn_unlock()`. The logoff variant needs only an ordinary (including guest-mapped) SMB session.\nUI:N - The attacker triggers everything by sending SMB2 requests to the listening ksmbd server; no action by any local user or administrator is involved.\nS:U - The corruption and its consequences stay within the kernel\u0027s own security authority on the SMB server host, with no crossing of a VM, sandbox, or IOMMU boundary.\nC:H - After the free, `set_sign_rsp()` HMACs the response with `sess-\u003esmb3signingkey` read from reclaimed slab memory and returns the result to the attacker, and `sess-\u003efile_table`/`sess-\u003etree_conns` lookups on freed xarrays yield attacker-influenced pointers, enabling disclosure of arbitrary kernel memory.\nI:H - `smb3_preauth_hash_rsp()` writes a 64-byte SHA-512 result through the `Preauth_HashValue` pointer read out of the freed object, giving a controlled kernel write once the slab is sprayed; the freed `file_table`/`tree_conns`/`user` fields additionally allow type confusion and control-flow hijacking.\nA:H - Even without successful exploitation the use-after-free dereferences freed slab memory and corrupts the allocator, producing kernel oopses and panics that take down the SMB server host, and it can be retriggered at will."
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-08-05T11:41:31.690Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/0f62358ce85b2d4c949ef1b648be01b29cec667a"
            },
            {
              "url": "https://git.kernel.org/stable/c/a9839c37fd813b432988f58a9d9dd59253d3eb2c"
            },
            {
              "url": "https://git.kernel.org/stable/c/5511999e9615e4318e9142d23b29bd1597befc08"
            },
            {
              "url": "https://git.kernel.org/stable/c/ee371898b53a9b9b51c02d22a8c31bfb86d45f0d"
            },
            {
              "url": "https://git.kernel.org/stable/c/7aa8804c0b67b3cb263a472d17f2cb50d7f1a930"
            }
          ],
          "title": "ksmbd: fix user-after-free from session log off",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2024-50086",
        "datePublished": "2024-10-29T00:50:29.284Z",
        "dateReserved": "2024-10-21T19:36:19.942Z",
        "dateUpdated": "2026-08-05T11:41:31.690Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.