CVE-2026-31476ksmbd: do not expire session on binding failure
- 8.2HighCVSS base score
- 0.50%Exploitation in 30 daysEPSS · top 57% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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().
Timeline
ID reserved
By Linux
- 44 days later
· 44 days later
Published
- 4 months later
· 4 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H |
| NVDNVD · Modified | 3.1 | High8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H |
- EPSS (exploitation in 30 days)
- 0.50% · top 57% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.2.
Affected products
- affected f5a544e3bab78142207e0242d22442db85ba1eff – < 4642ea35c03cf3d3558c009df4757cdb7af3f82d
- affected f5a544e3bab78142207e0242d22442db85ba1eff – < f5300690c23c5ac860499bb37dbc09cf43fd62e6
- affected f5a544e3bab78142207e0242d22442db85ba1eff – < 6fafc4c4238e538969f1375f9ecdc6587c53f1cc
- affected f5a544e3bab78142207e0242d22442db85ba1eff – < 1d1888b4a7aec518b707f6eca0bf08992c0e8da3
- affected f5a544e3bab78142207e0242d22442db85ba1eff – < a897064a457056acb976e20e3007cdf553de340f
- affected f5a544e3bab78142207e0242d22442db85ba1eff – < e0e5edc81b241c70355217de7e120c97c3429deb
- affected f5a544e3bab78142207e0242d22442db85ba1eff – < 9bbb19d21ded7d78645506f20d8c44895e3d0fb9
- affected 5.15
- unaffected < 5.15
- unaffected 5.15.209 – ≤ 5.15.*
- unaffected 6.1.168 – ≤ 6.1.*
- unaffected 6.6.131 – ≤ 6.6.*
- unaffected 6.12.80 – ≤ 6.12.*
- unaffected 6.18.21 – ≤ 6.18.*
- unaffected 6.19.11 – ≤ 6.19.*
- unaffected 7.0 – ≤ *
References
References7
- https://git.kernel.org/stable/c/4642ea35c03cf3d3558c009df4757cdb7af3f82d (opens in a new tab)
- https://git.kernel.org/stable/c/f5300690c23c5ac860499bb37dbc09cf43fd62e6 (opens in a new tab)
- https://git.kernel.org/stable/c/6fafc4c4238e538969f1375f9ecdc6587c53f1cc (opens in a new tab)
- https://git.kernel.org/stable/c/1d1888b4a7aec518b707f6eca0bf08992c0e8da3 (opens in a new tab)
- https://git.kernel.org/stable/c/a897064a457056acb976e20e3007cdf553de340f (opens in a new tab)
- https://git.kernel.org/stable/c/e0e5edc81b241c70355217de7e120c97c3429deb (opens in a new tab)
- https://git.kernel.org/stable/c/9bbb19d21ded7d78645506f20d8c44895e3d0fb9 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-24831 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-31476)Record last updated .