In the Linux kernel, the following vulnerability has been resolved: smb: client: fix heap overflow in cifsdosetacl() cifssetacl() validates…
CVE-2026-99110
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix heap overflow in cifsdosetacl() cifssetacl() validates ACL size using posixaclxattrsize(): 4 + (count 8) // 4-byte header + 8 bytes per ACE cifsdosetacl() then calls posixacltocifs() to write the CIFS wire format into the same buffer: 6 + (count 10) // 6-byte header + 10 bytes per ACE An ACL that passes the xattr-based check in cifssetacl() can overflow the heap when posixacltocifs() writes the larger CIFS format. Validate the CIFS format size against the remaining buffer space and USHRTMAX before converting--datacount is u16, so sizes above USHRTMAX truncate the on-wire packet length, causing the server to apply a partial ACL. Replace MaxDataCount = 1000 with min(CIFSMaxBufSize, USHRTMAX).
Assessment
- CVSS
- 7 (v3.1)
- Severity
- High
- EPSS
- 0.18% chance of exploitation in the next 30 days
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 28 October 2026
- Last updated
- 31 October 2026
- Affected
- Linux
- Assigner
- Linux
CVSS vectorCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
At the source
References
- https://git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249
- https://git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0
- https://git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98
- https://git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac
- https://git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29
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