CVE-2026-64392: Linux kernel · ksmbd: use opener credentials for delete-on-close
Affects Linux kernelSource CVE Database V5
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
Thin evidence
One scorer or none| CNA (Linux) | CVSS 3.1 | 9.1 |
|---|
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 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
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
- git.kernel.org/stable/c/3cb2e6e2a6798909507b9d695e4b80e685e72d26 (opens in a new tab)
- git.kernel.org/stable/c/f08b3f451f12eee4abd8a5981803bc36db84458b (opens in a new tab)
- git.kernel.org/stable/c/18c59109bb6fb816d5102171666f87cf1e29901d (opens in a new tab)
- git.kernel.org/stable/c/e72c15085b6d86f45d224d98aa75b5cace4aaab9 (opens in a new tab)
- git.kernel.org/stable/c/4b7059974549d278e30fe70e2a4e421f9839817d (opens in a new tab)
- git.kernel.org/stable/c/52e2f21911158ec961cd5aae19c56460db382af0 (opens in a new tab)