CVE-2026-90169: Linux kernel · ksmbd: free preauth sessions on connection teardown
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in effcf48d79d8aa53113d8289e140746f25ceb62c : update Linux kernel when convenient.
Data as of 30 Oct 2026, 12:51 UTC
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
Disclosed: evidence found.
CVE published 17 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- git.kernel.org/stable/c/1f60a88b2e0203e50f65b0fb9c32ecb0ae0aa683 (opens in a new tab)
- git.kernel.org/stable/c/effcf48d79d8aa53113d8289e140746f25ceb62c (opens in a new tab)
- git.kernel.org/stable/c/b62b1ebb25f0a19067ed5b1a86036b2dc98be44f (opens in a new tab)
- git.kernel.org/stable/c/a41a98ee16ae038751b6639decadaa3ce15ca18a (opens in a new tab)
- git.kernel.org/stable/c/8e2ebc77678832e981adc008d25cd8f67d08ebc4 (opens in a new tab)
- git.kernel.org/stable/c/06c7b1d731bc105a8644f1b70165ba8b9416cbab (opens in a new tab)