CVE-2026-64391: Linux kernel · ksmbd: use opener credentials for ADS I/O
Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in baa5e094886fffa7e6272edcb5e08be5ce28262c : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 39% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in baa5e094886fffa7e6272edcb5e08be5ce28262c, a8f5d39971bbad9340d49cd41b0e2da9452a649d, 52a56cf53ec834c44ac1b4d16d585f26613ee5ce +2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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– |
AI-suggested
A fix for this vulnerability has been implemented in the Linux kernel. Users should apply the official kernel updates that include this patch to ensure ADS I/O operations use the correct opener credentials. Since this is a kernel-level fix, upgrading to a patched kernel version is the recommended remediation. Patch status is not explicitly confirmed in the provided data; users should verify with the Linux kernel vendor advisory for the exact fixed versions and update accordingly.
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: use opener credentials for ADS I/O Alternate data streams are stored as xattrs. Unlike regular file I/O, their read and write paths therefore call VFS xattr helpers which recheck inode permissions and LSM policy using the current task credentials. Run ADS I/O with the credentials captured when the SMB handle was opened.
References
- nvd.nist.gov/vuln/detail/CVE-2026-64391 (opens in a new tab)
- git.kernel.org/stable/c/2b4592cea214683de0f2ce6f8c22c097fb0ea1ab (opens in a new tab)
- git.kernel.org/stable/c/52a56cf53ec834c44ac1b4d16d585f26613ee5ce (opens in a new tab)
- git.kernel.org/stable/c/a8f5d39971bbad9340d49cd41b0e2da9452a649d (opens in a new tab)
- git.kernel.org/stable/c/baa5e094886fffa7e6272edcb5e08be5ce28262c (opens in a new tab)