Bug 2464482 (CVE-2026-31704) - CVE-2026-31704 kernel: ksmbd: use check_add_overflow() to prevent u16 DACL size overflow
Summary: CVE-2026-31704 kernel: ksmbd: use check_add_overflow() to prevent u16 DACL si...
Keywords:
Status: NEW
Alias: CVE-2026-31704
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-01 15:09 UTC by OSIDB Bzimport
Modified: 2026-05-01 20:00 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2026-05-01 15:09:16 UTC
In the Linux kernel, the following vulnerability has been resolved:

ksmbd: use check_add_overflow() to prevent u16 DACL size overflow

set_posix_acl_entries_dacl() and set_ntacl_dacl() accumulate ACE sizes
in u16 variables. When a file has many POSIX ACL entries, the
accumulated size can wrap past 65535, causing the pointer arithmetic
(char *)pndace + *size to land within already-written ACEs. Subsequent
writes then overwrite earlier entries, and pndacl->size gets a
truncated value.

Use check_add_overflow() at each accumulation point to detect the
wrap before it corrupts the buffer, consistent with existing
check_mul_overflow() usage elsewhere in smbacl.c.


Note You need to log in before you can comment on or make changes to this bug.