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VulnerabilityPublished Updated

CVE-2026-64391: Linux kernel · ksmbd: use opener credentials for ADS I/O

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical · fixed in baa5e094886fffa7e6272edcb5e08be5ce28262c : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: 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 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ f44158485826c076335d6860d35872271a83791d, < baa5e094886fffa7e6272edcb5e08be5ce28262c
Fixed in
  • baa5e094886fffa7e6272edcb5e08be5ce28262c
LinuxLinuxAffected
  • ≥ f44158485826c076335d6860d35872271a83791d, < a8f5d39971bbad9340d49cd41b0e2da9452a649d
Fixed in
  • a8f5d39971bbad9340d49cd41b0e2da9452a649d
LinuxLinuxAffected
  • ≥ f44158485826c076335d6860d35872271a83791d, < 52a56cf53ec834c44ac1b4d16d585f26613ee5ce
Fixed in
  • 52a56cf53ec834c44ac1b4d16d585f26613ee5ce
LinuxLinuxAffected
  • ≥ f44158485826c076335d6860d35872271a83791d, < 2b4592cea214683de0f2ce6f8c22c097fb0ea1ab
Fixed in
  • 2b4592cea214683de0f2ce6f8c22c097fb0ea1ab
LinuxLinuxAffected
  • ≥ f44158485826c076335d6860d35872271a83791d, < 2ad5509dd576ae16d252d4698daf03002f9e0234
Fixed in
  • 2ad5509dd576ae16d252d4698daf03002f9e0234
LinuxLinuxAffected
  • =5.15
Fixed in–

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

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