CVE-2026-98112 (GCVE-0-2026-98112)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:35 – Updated: 2026-09-25 14:42
VLAI
Title
ksmbd: fix listener task lifetime on netdev events
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix listener task lifetime on netdev events The listener thread exits when its listening socket is shutdown. The netdevice notifier shuts down the socket before calling kthread_stop(), so the task_struct can be freed before kthread_stop() gets its reference. Create the listener in a stopped state and hold an extra task_struct reference until kthread_stop_put() completes. Also stop and release listeners before freeing their interface records during TCP teardown.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 3316a8fc840d82fad5efcf76ad0ea3f76fdca209 , < 40581f10c1e56238b157af5f260b8f9518a0cbc1 (git)
Affected: 3316a8fc840d82fad5efcf76ad0ea3f76fdca209 , < a506290f59e1c6ce9ac0a13158640bb8fee93471 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.19
Unaffected: 0 , < 6.19 (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/transport_tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "40581f10c1e56238b157af5f260b8f9518a0cbc1",
              "status": "affected",
              "version": "3316a8fc840d82fad5efcf76ad0ea3f76fdca209",
              "versionType": "git"
            },
            {
              "lessThan": "a506290f59e1c6ce9ac0a13158640bb8fee93471",
              "status": "affected",
              "version": "3316a8fc840d82fad5efcf76ad0ea3f76fdca209",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/smb/server/transport_tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "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": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc2",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix listener task lifetime on netdev events\n\nThe listener thread exits when its listening socket is shutdown. The\nnetdevice notifier shuts down the socket before calling kthread_stop(), so\nthe task_struct can be freed before kthread_stop() gets its reference.\n\nCreate the listener in a stopped state and hold an extra task_struct\nreference until kthread_stop_put() completes. Also stop and release\nlisteners before freeing their interface records during TCP teardown."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is kthread_stop() on an already-exited listener, reached from ksmbd_netdev_event(NETDEV_DOWN). That event comes from local rtnetlink link up/down. No SMB message carries attacker data to this path, so it is not remote.\nAC:L - The attacker starts the race: kernel_sock_shutdown() makes the listener exit before kthread_stop() takes its reference. The attacker can repeat it at will by toggling a same-named link. Each NETDEV_UP makes create_socket() start a new listener, so the narrow window can be retried as many times as needed.\nPR:L - ksmbd_netdev_event() matches iface names without checking the network namespace. An unprivileged user in `unshare -Urn` can down their own `lo`, or a veth named like a host interface, with only CAP_NET_ADMIN inside the user namespace, and so run the teardown of the host listener.\nUI:N - Nothing is needed from an admin or victim beyond ksmbd already running. The attacker sends the netlink link up/down requests themselves inside their own network namespace.\nS:U - This is memory corruption inside the kernel that leads to local privilege escalation or a crash within the same kernel authority. It does not cross a hypervisor or other separate security boundary.\nC:H - After the listener task_struct is freed and reallocated, kthread_stop() reads to_kthread(k) and kthread-\u003eresult through a dangling pointer. The attacker can control the reclaimed object, which enables kernel memory disclosure.\nI:H - kthread_stop() writes to freed memory: it increments the refcount, does set_bit() on kthread-\u003eflags, then calls wake_up_process() and put_task_struct() on the stale task. This corrupts whatever object has reclaimed the memory and can be groomed into a write or an extra free.\nA:H - Using the freed task_struct/kthread in kthread_stop() under rtnl can cause an oops, a refcount underflow or a hang. Each trigger also tears down ksmbd\u0027s real host listener on port 445, so the server stops accepting connections."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T14:42:06.515Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/40581f10c1e56238b157af5f260b8f9518a0cbc1"
        },
        {
          "url": "https://git.kernel.org/stable/c/a506290f59e1c6ce9ac0a13158640bb8fee93471"
        }
      ],
      "title": "ksmbd: fix listener task lifetime on netdev events",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98112",
    "datePublished": "2026-09-25T10:35:59.319Z",
    "dateReserved": "2026-09-25T10:25:14.316Z",
    "dateUpdated": "2026-09-25T14:42:06.515Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-98112",
      "date": "2026-09-26",
      "epss": "0.0012",
      "percentile": "0.01643"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "fs/smb/server/transport_tcp.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "40581f10c1e56238b157af5f260b8f9518a0cbc1",
                    "status": "affected",
                    "version": "3316a8fc840d82fad5efcf76ad0ea3f76fdca209",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "a506290f59e1c6ce9ac0a13158640bb8fee93471",
                    "status": "affected",
                    "version": "3316a8fc840d82fad5efcf76ad0ea3f76fdca209",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "fs/smb/server/transport_tcp.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "6.19"
                  },
                  {
                    "lessThan": "6.19",
                    "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: fix listener task lifetime on netdev events\n\nThe listener thread exits when its listening socket is shutdown. The\nnetdevice notifier shuts down the socket before calling kthread_stop(), so\nthe task_struct can be freed before kthread_stop() gets its reference.\n\nCreate the listener in a stopped state and hold an extra task_struct\nreference until kthread_stop_put() completes. Also stop and release\nlisteners before freeing their interface records during TCP teardown."
          }
        ],
        "id": "CVE-2026-98112",
        "lastModified": "2026-09-25T15:18:06.070",
        "metrics": {
          "cvssMetricV31": [
            {
              "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": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-25T11:17:42.340",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/40581f10c1e56238b157af5f260b8f9518a0cbc1"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/a506290f59e1c6ce9ac0a13158640bb8fee93471"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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.