DEBIAN-CVE-2026-43490

Advisory lineage Upstream: 1 Downstream: 0
Upstream
CVE-2026-43490
Published: 15 May 2026, 06:16
Last modified:15 Jun 2026, 09:00

Vulnerability Summary

Overall Risk (default)
medium
35/100
CVSS Score
8.8 HIGH
3.1 (osv_debian)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

15 May 2026, 06:16
Published
Vulnerability first disclosed
15 Jun 2026, 09:00
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate inherited ACE SID length smb_inherit_dacl() walks the parent directory DACL loaded from the security descriptor xattr. It verifies that each ACE contains the fixed SID header before using it, but does not verify that the variable-length SID described by sid.num_subauth is fully contained in the ACE. A malformed inheritable ACE can advertise more subauthorities than are present in the ACE. compare_sids() may then read past the ACE. smb_set_ace() also clamps the copied destination SID, but used the unchecked source SID count to compute the inherited ACE size. That could advance the temporary inherited ACE buffer pointer and nt_size accounting past the allocated buffer. Fix this by validating the parent ACE SID count and SID length before using the SID during inheritance. Compute the inherited ACE size from the copied SID so the size matches the bounded destination SID. Reject the inherited DACL if size accumulation would overflow smb_acl.size or the security descriptor allocation size.

CVSS Metrics

  • v3.1•HIGH•Score: 8.8CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Systems

  • debian•linux

    all | all | all | < 6.12.88-1 | < 7.0.7-1

References (1)