CVE-2026-46195

CRITICAL

smb: client: validate dacloffset before building DACL pointers

Title source: cna
STIX 2.1

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building DACL pointers parse_sec_desc(), build_sec_desc(), and the chown path in id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd before proving a DACL header fits inside the returned security descriptor. On 32-bit builds a malicious server can return dacloffset near U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip past the later pointer-based bounds checks. build_sec_desc() and id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped pointer in the chmod/chown rewrite paths. Validate dacloffset numerically before building any DACL pointer and reuse the same helper at the three DACL entry points.

Scores

CVSS v3 9.8
EPSS 0.0050
EPSS Percentile 38.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Details

CWE
CWE-476
Status published
Products (15)
Linux/Linux < 5.12
Linux/Linux 5.12
Linux/Linux 6.12.88 - 6.12.*
Linux/Linux 6.18.30 - 6.18.*
Linux/Linux 6.6.140 - 6.6.*
Linux/Linux 7.0.7 - 7.0.*
Linux/Linux 7.1
Linux/Linux 7.1-rc3
Linux/Linux bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 - 3b1ddba19e77ee35241cd27f16dc3e8d14e08db7
Linux/Linux bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 - 8bd07e417b6bda67e317920584e48cb6ee442a8a
... and 5 more
Published May 28, 2026
Tracked Since May 28, 2026