SB20260727186 - Improper input validation in Linux kernel smb client
Published: July 27, 2026
Security Bulletin ID
SB20260727186
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Improper input validation (CVE-ID: CVE-2026-64379)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to modify file mode bits.
The vulnerability exists due to improper input validation in parse_dacl() when processing a server-provided NFS mode SID. A remote attacker can provide crafted mode values to modify file mode bits.
The issue occurs when modefromsid is active.
Remediation
Install update from vendor's website.
References
- https://git.kernel.org/stable/c/08c600b7e1818539ba5efee4cdb06215c245ca78
- https://git.kernel.org/stable/c/5f6f2241034f189c69d4d0b5f8fe24a0c25b0c14
- https://git.kernel.org/stable/c/b84e002e0df26bbc6cbd3ca01b8212601fe0ae7d
- https://git.kernel.org/stable/c/c6c484a7d5bff6b929a86d7ed5130f29834c6a0d
- https://git.kernel.org/stable/c/e3d9c7160d483fc8f9e225aafad8ecbbc43f3151
- https://git.kernel.org/stable/c/ee2216dbdf0c677e89bb43e03247dba590ed00ef
- https://git.kernel.org/stable/c/f511807feee7cb29b61bdfa86472c7e9e2e5df94
- https://git.kernel.org/stable/c/f80add1bfb3425100a325b14f19648e75669a954