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VulnerabilityPublished Updated

CVE-2026-64392: Linux kernel · ksmbd: use opener credentials for delete-on-close

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · CVSS 9.1 Critical · fixed in f08b3f451f12eee4abd8a5981803bc36db84458b : patch Linux kernel as a priority.

Data as of 30 Oct 2026, 13:32 UTC

CVSS 3.1 base score
9.1Critical
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Linux)CVSS 3.19.1
Patch
Available – fixed in f08b3f451f12eee4abd8a5981803bc36db84458b, e72c15085b6d86f45d224d98aa75b5cace4aaab9, 52e2f21911158ec961cd5aae19c56460db382af0 +3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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. 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
  • ≥ f44158485826c076335d6860d35872271a83791d, < f08b3f451f12eee4abd8a5981803bc36db84458b
Fixed in
  • f08b3f451f12eee4abd8a5981803bc36db84458b
LinuxLinuxAffected
  • ≥ f44158485826c076335d6860d35872271a83791d, < e72c15085b6d86f45d224d98aa75b5cace4aaab9
Fixed in
  • e72c15085b6d86f45d224d98aa75b5cace4aaab9
LinuxLinuxAffected
  • ≥ f44158485826c076335d6860d35872271a83791d, < 52e2f21911158ec961cd5aae19c56460db382af0
Fixed in
  • 52e2f21911158ec961cd5aae19c56460db382af0
LinuxLinuxAffected
  • ≥ f44158485826c076335d6860d35872271a83791d, < 18c59109bb6fb816d5102171666f87cf1e29901d
Fixed in
  • 18c59109bb6fb816d5102171666f87cf1e29901d
LinuxLinuxAffected
  • ≥ f44158485826c076335d6860d35872271a83791d, < 4b7059974549d278e30fe70e2a4e421f9839817d
Fixed in
  • 4b7059974549d278e30fe70e2a4e421f9839817d
LinuxLinuxAffected
  • ≥ f44158485826c076335d6860d35872271a83791d, < 3cb2e6e2a6798909507b9d695e4b80e685e72d26
Fixed in
  • 3cb2e6e2a6798909507b9d695e4b80e685e72d26

AI-suggested

This vulnerability has been fixed in the Linux kernel after version 5.15, as indicated by multiple fixed commits. Users and administrators should update their Linux kernel to a version including these fixes to mitigate the issue. No additional mitigation is required beyond applying the official patch.

Description

CVE-2026-64392 is a critical vulnerability in the Linux kernel's ksmbd component where delete-on-close operations use incorrect credentials, allowing bypass of filesystem permission checks. The flaw arises because delete-on-close actions run with ksmbd worker credentials instead of the authenticated user's credentials. This issue has been fixed by ensuring these operations run with the credentials captured when the file handle was opened, preserving proper user permissions and capability restrictions.

References

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