CVE-2026-31704
Description
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Linux kernel Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | 6.6.136 |
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Windows Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 6.12.85-1 |
| sid | Fixed | 7.0.3-1 |
| forky | Fixed | 7.0.3-1 |
| bullseye | Fixed | 0 |
| bookworm | Affected | — |
References
- https://git.kernel.org/stable/c/299f962c0b02d048fb45d248b4da493d03f3175d
- https://git.kernel.org/stable/c/5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43
- https://git.kernel.org/stable/c/8d5729350b236896f51379588d9a690b7fafb8db
- https://git.kernel.org/stable/c/e1955a94b6f17f4b058afa955a6f187eb3ed7615
- https://git.kernel.org/stable/c/ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7
- https://www.suse.com/security/cve/CVE-2026-31704.html
- https://security-tracker.debian.org/tracker/CVE-2026-31704
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-31704
- https://git.kernel.org/stable/c/41e53a773db6342ac9a689ee5ba635c31744c9f0
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.