CVE-2026-68097

Summary

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: validate ACE size against SID sub-authorities

set_ntacl_dacl() validates sid.num_subauth before copying an ACE, but does not verify that the declared ACE size contains all sub-authorities described by that field. An undersized ACE can therefore be copied and later make the POSIX ACL deduplication walk inspect data beyond the copied ACE boundary.

The existing initial bound check is also too small. It only ensures that the ACE size field is accessible before set_ntacl_dacl() reads sid.num_subauth farther into the input buffer.

Require enough input for the fixed SID header before accessing num_subauth, reject ACEs smaller than that header, and skip ACEs whose declared size cannot contain the complete SID. This makes the validation consistent with the other ACE walk paths.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b7cb5bf0855470799f12da825de91e48951b3876affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 62d80d7c2d9428085e7458ad4c06ca8c0984039baffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 337022d9dfac441c3b35e4455a51aa981996e02eaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 61fd3559199f7fa693dcbff35e59477e24af041aaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5152c6d49e3fd4e9f2e857c57527aead752f1f87affected
LinuxLinux0 < 6.6.148affected
LinuxLinux0 < 6.12.101affected
LinuxLinux0 < 6.18.42affected
LinuxLinux0 < 7.1.6affected
LinuxLinux6.6.148 <= 6.6.*unaffected
LinuxLinux6.12.101 <= 6.12.*unaffected
LinuxLinux6.18.42 <= 6.18.*unaffected
LinuxLinux7.1.6 <= 7.1.*unaffected
LinuxLinux7.2-rc5 <= *unaffected

Weaknesses

References