CVE-2026-64393Critical permission bypass in Linux ksmbd
In the Linux kernel, the following vulnerability has been resolved: ksmbd: run set info with opener credentials SMB2 SET_INFO handlers call path-based VFS helpers after checking the access mask granted to the SMB handle. Those helpers perform their owner, inode permission and LSM checks using the current ksmbd worker credentials. Run the complete SET_INFO dispatch with the credentials captured when the handle was opened. This also removes the separate security information credential setup and keeps all SET_INFO classes under one credential scope. Direct override_creds() is used because it can nest with the request credential overrides already used by rename and link helpers.
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Se ha identificado una vulnerabilidad crítica en el componente ksmbd del kernel de Linux. El fallo permite que las solicitudes SMB2 SET_INFO evadan ciertas verificaciones de permisos al utilizar credenciales incorrectas, lo que podría resultar en un escalamiento de privilegios o acceso no autorizado a archivos.
Severity
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:HEPSS
Technical description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: run set info with opener credentials SMB2 SET_INFO handlers call path-based VFS helpers after checking the access mask granted to the SMB handle. Those helpers perform their owner, inode permission and LSM checks using the current ksmbd worker credentials. Run the complete SET_INFO dispatch with the credentials captured when the handle was opened. This also removes the separate security information credential setup and keeps all SET_INFO classes under one credential scope. Direct override_creds() is used because it can nest with the request credential overrides already used by rename and link helpers.
References
- https://git.kernel.org/stable/c/0ce682867fd506f61f40c76bde7e4205bde34e87
- https://git.kernel.org/stable/c/20ee516a62989a8d505ee432f9e59525ea23984e
- https://git.kernel.org/stable/c/5cbabf3a71575cd31bc7785d92d4ab42338a654b
- https://git.kernel.org/stable/c/8cc9ec711f5255167247a9ab6a7179b787426ed7
- https://git.kernel.org/stable/c/b35afd5cf8fab236ef21117e42ee45691d4ffa7b
- https://git.kernel.org/stable/c/b383bcad3d2fe634b26efbce53e22bbb5753a520