Vulnerability-Lookup

FKIE_CVE-2026-98115

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 15:18

Severity

8.8 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: ksmbd: safely drain sessions during logoff SMB3 multichannel allows requests for one session to run on multiple connections. Wait for all channels bound to a session before freeing shared session objects. A deferred byte-range lock remains counted as a running request and only wakes when its file closes. Wake blocked locks during the drain without unpublishing or modifying their file objects. Synchronous CANCEL requests must invoke their cancellation callback to wake pending operations, while CHANGE_NOTIFY completion remains specific to the asynchronous path. Serialize session teardown with channel registration and previous-session cleanup, and use atomic work-state transitions so LOGOFF, CANCEL, and connection teardown invoke cancellation callbacks only once.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a7e6df0bb92642bee4431b2b85c69ada1e463b21
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d12168084c8c1b6d883c8eca5853929ac5136a9e

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/connection.c",
            "fs/smb/server/mgmt/user_session.c",
            "fs/smb/server/mgmt/user_session.h",
            "fs/smb/server/smb2pdu.c",
            "fs/smb/server/vfs_cache.c",
            "fs/smb/server/vfs_cache.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a7e6df0bb92642bee4431b2b85c69ada1e463b21",
              "status": "affected",
              "version": "76e98a158b207771a6c9a0de0a60522a446a3447",
              "versionType": "git"
            },
            {
              "lessThan": "d12168084c8c1b6d883c8eca5853929ac5136a9e",
              "status": "affected",
              "version": "76e98a158b207771a6c9a0de0a60522a446a3447",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "118fd997612d1efc94a86c307c6c6d659ebe29fc",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c1e55020534c4aafbc38d8f5c4583ff30755ac18",
              "versionType": "git"
            },
            {
              "lessThan": "6.7",
              "status": "affected",
              "version": "6.6.48",
              "versionType": "semver"
            },
            {
              "lessThan": "6.11",
              "status": "affected",
              "version": "6.10.7",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/connection.c",
            "fs/smb/server/mgmt/user_session.c",
            "fs/smb/server/mgmt/user_session.h",
            "fs/smb/server/smb2pdu.c",
            "fs/smb/server/vfs_cache.c",
            "fs/smb/server/vfs_cache.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: safely drain sessions during logoff\n\nSMB3 multichannel allows requests for one session to run on multiple\nconnections. Wait for all channels bound to a session before freeing\nshared session objects.\n\nA deferred byte-range lock remains counted as a running request and only\nwakes when its file closes. Wake blocked locks during the drain without\nunpublishing or modifying their file objects. Synchronous CANCEL requests\nmust invoke their cancellation callback to wake pending operations, while\nCHANGE_NOTIFY completion remains specific to the asynchronous path.\n\nSerialize session teardown with channel registration and previous-session\ncleanup, and use atomic work-state transitions so LOGOFF, CANCEL, and\nconnection teardown invoke cancellation callbacks only once."
    }
  ],
  "id": "CVE-2026-98115",
  "lastModified": "2026-09-25T15:18:06.270",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-25T11:17:42.667",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a7e6df0bb92642bee4431b2b85c69ada1e463b21"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d12168084c8c1b6d883c8eca5853929ac5136a9e"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-98115 (GCVE-0-2026-98115)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:36 – Updated: 2026-09-25 14:42

Title

ksmbd: safely drain sessions during logoff

Summary

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/a7e6df0bb92642bee…
https://git.kernel.org/stable/c/d12168084c8c1b6d8…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 76e98a158b207771a6c9a0de0a60522a446a3447 , < a7e6df0bb92642bee4431b2b85c69ada1e463b21 (git) Affected: 76e98a158b207771a6c9a0de0a60522a446a3447 , < d12168084c8c1b6d883c8eca5853929ac5136a9e (git) Affected: 118fd997612d1efc94a86c307c6c6d659ebe29fc (git) Affected: c1e55020534c4aafbc38d8f5c4583ff30755ac18 (git) Affected: 6.6.48 , < 6.7 (semver) Affected: 6.10.7 , < 6.11 (semver)
Linux	Linux	Affected: 6.11 Unaffected: 0 , < 6.11 (semver) Unaffected: 7.2.7 , ≤ 7.2.* (semver) Unaffected: 7.3-rc2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/connection.c",
            "fs/smb/server/mgmt/user_session.c",
            "fs/smb/server/mgmt/user_session.h",
            "fs/smb/server/smb2pdu.c",
            "fs/smb/server/vfs_cache.c",
            "fs/smb/server/vfs_cache.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a7e6df0bb92642bee4431b2b85c69ada1e463b21",
              "status": "affected",
              "version": "76e98a158b207771a6c9a0de0a60522a446a3447",
              "versionType": "git"
            },
            {
              "lessThan": "d12168084c8c1b6d883c8eca5853929ac5136a9e",
              "status": "affected",
              "version": "76e98a158b207771a6c9a0de0a60522a446a3447",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "118fd997612d1efc94a86c307c6c6d659ebe29fc",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "c1e55020534c4aafbc38d8f5c4583ff30755ac18",
              "versionType": "git"
            },
            {
              "lessThan": "6.7",
              "status": "affected",
              "version": "6.6.48",
              "versionType": "semver"
            },
            {
              "lessThan": "6.11",
              "status": "affected",
              "version": "6.10.7",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/connection.c",
            "fs/smb/server/mgmt/user_session.c",
            "fs/smb/server/mgmt/user_session.h",
            "fs/smb/server/smb2pdu.c",
            "fs/smb/server/vfs_cache.c",
            "fs/smb/server/vfs_cache.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc2",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.6.48",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.10.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: safely drain sessions during logoff\n\nSMB3 multichannel allows requests for one session to run on multiple\nconnections. Wait for all channels bound to a session before freeing\nshared session objects.\n\nA deferred byte-range lock remains counted as a running request and only\nwakes when its file closes. Wake blocked locks during the drain without\nunpublishing or modifying their file objects. Synchronous CANCEL requests\nmust invoke their cancellation callback to wake pending operations, while\nCHANGE_NOTIFY completion remains specific to the asynchronous path.\n\nSerialize session teardown with channel registration and previous-session\ncleanup, and use atomic work-state transitions so LOGOFF, CANCEL, and\nconnection teardown invoke cancellation callbacks only once."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The racing teardowns start from SMB2 messages that ksmbd receives over TCP/445. They are an SMB2 LOGOFF handled by smb2_session_logoff(), and a SESSION_SETUP carrying PreviousSessionId handled by destroy_previous_session(). Requests in flight on other bound channels are also affected. All of these are sent by the remote client.\nAC:L - The attacker controls both sides of the race by opening several TCP connections to the same session. Before the fix, smb2_session_logoff() only waited for its own connection (ksmbd_conn_wait_idle). It also had no tearing_down guard against a concurrent destroy_previous_session() or a second LOGOFF, so the attacker can retry the race at will.\nPR:L - Both LOGOFF and a PreviousSessionId reconnect need a valid authenticated session. destroy_previous_session() also checks that the user name and passkey match the previous session\u0027s user. So the attacker must be an ordinary authenticated SMB user, not an unauthenticated one.\nUI:N - The attacker\u0027s own SMB requests on their own connections drive the whole sequence. No admin or victim action is needed.\nS:U - The corruption stays within the kernel\u0027s own security authority: ksmbd session, file table and tree-connect objects. No hypervisor or IOMMU boundary is crossed.\nC:H - The session\u0027s file table can be torn down while it is still in use. ksmbd_close_session_fds() and ksmbd_destroy_file_table() can run at the same time, and requests on other channels can still hold objects from the table being freed. That makes a use-after-free or double free of kernel heap objects, which a heap spray can turn into a memory read.\nI:H - A use-after-free or double free of ksmbd_file and session objects reached from the network lets the attacker reallocate the freed memory with their own data. That can corrupt kernel memory and potentially hijack control flow.\nA:H - Freeing session objects during concurrent teardown can oops or panic the kernel. Deferred byte-range locks that never wake can also hang the drain. The attacker can repeat either on demand."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T14:42:07.560Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a7e6df0bb92642bee4431b2b85c69ada1e463b21"
        },
        {
          "url": "https://git.kernel.org/stable/c/d12168084c8c1b6d883c8eca5853929ac5136a9e"
        }
      ],
      "title": "ksmbd: safely drain sessions during logoff",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98115",
    "datePublished": "2026-09-25T10:36:01.119Z",
    "dateReserved": "2026-09-25T10:25:14.317Z",
    "dateUpdated": "2026-09-25T14:42:07.560Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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FKIE_CVE-2026-98115

CVE-2026-98115 (GCVE-0-2026-98115)

Tags

Sightings

Nomenclature

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