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VulnerabilityPublished Updated

CVE-2026-90169: Linux kernel · ksmbd: free preauth sessions on connection teardown

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in effcf48d79d8aa53113d8289e140746f25ceb62c : update Linux kernel when convenient.

Data as of 30 Oct 2026, 12:51 UTC

Severity
Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none
Patch
Available – fixed in effcf48d79d8aa53113d8289e140746f25ceb62c, b62b1ebb25f0a19067ed5b1a86036b2dc98be44f, a41a98ee16ae038751b6639decadaa3ce15ca18a +3

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 17 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < effcf48d79d8aa53113d8289e140746f25ceb62c
Fixed in
  • effcf48d79d8aa53113d8289e140746f25ceb62c
LinuxLinuxAffected
  • ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < b62b1ebb25f0a19067ed5b1a86036b2dc98be44f
Fixed in
  • b62b1ebb25f0a19067ed5b1a86036b2dc98be44f
LinuxLinuxAffected
  • ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < a41a98ee16ae038751b6639decadaa3ce15ca18a
Fixed in
  • a41a98ee16ae038751b6639decadaa3ce15ca18a
LinuxLinuxAffected
  • ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < 8e2ebc77678832e981adc008d25cd8f67d08ebc4
Fixed in
  • 8e2ebc77678832e981adc008d25cd8f67d08ebc4
LinuxLinuxAffected
  • ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < 06c7b1d731bc105a8644f1b70165ba8b9416cbab
Fixed in
  • 06c7b1d731bc105a8644f1b70165ba8b9416cbab
LinuxLinuxAffected
  • ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < 1f60a88b2e0203e50f65b0fb9c32ecb0ae0aa683
Fixed in
  • 1f60a88b2e0203e50f65b0fb9c32ecb0ae0aa683

AI-suggested

A fix is available in the Linux kernel as indicated by multiple fixed commit versions. Users should update to a kernel version that includes these fixes to remediate the issue. No additional mitigation actions are specified or required beyond applying the official patch.

Description

A vulnerability in the Linux kernel's ksmbd component involves improper cleanup of preauthentication sessions when a client disconnects before completing authentication. Specifically, SMB3.1.1 multichannel binding retains a preauth_session object allocated during the NTLM negotiate phase, which is not freed if the client disconnects early. This can lead to resource leakage. The issue has been fixed by ensuring all preauthentication sessions are released during connection teardown.

References

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