CVE-2026-43350
In the Linux kernel, the following vulnerability has been resolved: smb: client: require a full NFS mode SID before reading mode bits parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS mode SID and reads sid.sub_auth[2] to recover the…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.22%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: smb: client: require a full NFS mode SID before reading mode bits parse_dacl() treats an ACE SID matching sid_unix_NFS_mode as an NFS mode SID and reads sid.sub_auth[2] to recover the mode bits. That assumes the ACE carries three subauthorities, but compare_sids() only compares min(a, b) subauthorities. A malicious server can return an ACE with num_subauth = 2 and sub_auth[] = {88, 3}, which still matches sid_unix_NFS_mode and then drives the sub_auth[2] read four bytes past the end of the ACE. Require num_subauth >= 3 before treating the ACE as an NFS mode SID. This keeps the fix local to the special-SID mode path without changing compare_sids() semantics for the rest of cifsacl.
- CVSS 3.1
- 7.6 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
- EPSS
- 0.22% probability · 13th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/1592a6cd6f653f2d24572a6976c7a775b19f4940
- https://git.kernel.org/stable/c/23b54d6cc3ef30a51d984dc74364f24039ae2ecb
- https://git.kernel.org/stable/c/2757ad3e4b6f9e0fed4c7739594e702abc5cab21Patch
- https://git.kernel.org/stable/c/38a69f08ee82c450d3e4168707fff2e317dc3ff7Patch
- https://git.kernel.org/stable/c/8bd4cad3f458d11650d51c2d24b03fb1770ae6cc
- https://git.kernel.org/stable/c/b53b8e98c23310294fc45fc686db5ee860311896Patch
- https://git.kernel.org/stable/c/c8eef12af1cc73031639ea7cf16e0b10e2536b0bPatch
- https://git.kernel.org/stable/c/f8488c07bea2431ee12a6067d736578064fa46b4Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.