Vulnerability in Linux

[ Description ]Official description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix heap overflow in cifs_do_set_acl() cifs_set_acl() validates ACL size using posix_acl_xattr_size(): 4 + (count * 8) // 4-byte header + 8 bytes per ACE cifs_do_set_acl() then calls posix_acl_to_cifs() 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 cifs_set_acl() can overflow the heap when posix_acl_to_cifs() writes the larger CIFS format. Validate the CIFS format size against the remaining buffer space and USHRT_MAX before converting--data_count is __u16, so sizes above USHRT_MAX truncate the on-wire packet length, causing the server to apply a partial ACL. Replace MaxDataCount = 1000 with min(CIFSMaxBufSize, USHRT_MAX).

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund28 Oct 2026WID-SEC-2026-4224

  Linux Kernel: Multiple vulnerabilities allow an unspecified attack Translated from German

  CVE-2026-99116CVE-2026-99143CVE-2026-99170+113 more CVEs

[ References ]References

• git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29
• git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac
• git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249
• git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0
• git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98