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CVE-2026-31476

CVE-2026-31476

published

In the Linux kernel, the following vulnerability has been resolved: ksmbd: do not expire session on binding failure When a multichannel session binding request fails (e.g. wrong password), the error path unconditionally sets sess->state = SMB2_SESSION_EXPIRED. However, during binding, sess points to the target session looked up via ksmbd_session_lookup_slowpath() -- which belongs to another connection's user. This allows a remote attacker to invalidate any active session by simply sending a binding request with a wrong password (DoS). Fix this by skipping session expiration when the failed request was a binding attempt, since the session does not belong to the current connection. The reference taken by ksmbd_session_lookup_slowpath() is still correctly released via ksmbd_user_session_put().

Technical severity8.2 highCVSS 3.1 · NVD: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published2026-04-22Source updated 2026-11-11

Collected2026-11-121 attributed source

Fixes and workarounds

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
linux_kernel linux	≥ 5.15.1; < 6.1.168 (affected, custom)	NVD
linux_kernel linux	≥ 6.2; < 6.6.131 (affected, custom)	NVD
linux_kernel linux	≥ 6.7; < 6.12.80 (affected, custom)	NVD
linux_kernel linux	≥ 6.13; < 6.18.21 (affected, custom)	NVD
linux_kernel linux	≥ 6.19; < 6.19.11 (affected, custom)	NVD
linux_kernel linux	5.15 (affected, custom)	NVD
linux_kernel linux	7.0 (affected, custom)	NVD

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

NVD applicability configurations (1)

These expressions retain AND/OR operators, negation, and required environmental products. A listed product is not sufficient to establish exposure when additional conditions apply.

[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.1.168",
            "versionStartIncluding": "5.15.1",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.6.131",
            "versionStartIncluding": "6.2",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.12.80",
            "versionStartIncluding": "6.7",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.18.21",
            "versionStartIncluding": "6.13",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.19.11",
            "versionStartIncluding": "6.19",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:5.15:-:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 8.2 high	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H`	NVD: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://git.kernel.org/stable/c/1d1888b4a7aec518b707f6eca0bf08992c0e8da3416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/4642ea35c03cf3d3558c009df4757cdb7af3f82d416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/6fafc4c4238e538969f1375f9ecdc6587c53f1cc416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/9bbb19d21ded7d78645506f20d8c44895e3d0fb9416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/a897064a457056acb976e20e3007cdf553de340f416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/e0e5edc81b241c70355217de7e120c97c3429deb416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/f5300690c23c5ac860499bb37dbc09cf43fd62e6416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch

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