CRITICAL: CVE-2026-31444 (CVSS 9.8) — multiple products

CVE: CVE-2026-31444

CVSS: 9.8 (3.1) — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: CRITICAL

Status: Critical advisory

Affected

_See vendor advisory_

Summary

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix use-after-free and NULL deref in smb_grant_oplock()

smb_grant_oplock() has two issues in the oplock publication sequence:

1) opinfo is linked into ci->m_op_list (via opinfo_add) before

add_lease_global_list() is called. If add_lease_global_list()

fails (kmalloc returns NULL), the error path frees the opinfo

via __free_opinfo() while it is still linked in ci->m_op_list.

Concurrent m_op_list readers (opinfo_get_list, or direct iteration

in smb_break_all_levII_oplock) dereference the freed node.

2) opinfo->o_fp is assigned after add_lease_global_list() publishes

the opinfo on the global lease list. A concurrent

find_same_lease_key() can walk the lease list and dereference

opinfo->o_fp->f_ci while o_fp is still NULL.

Fix by restructuring the publication sequence to eliminate post-publish

failure:

Set opinfo->o_fp before any list publication (fixes NULL deref).
Preallocate lease_table via alloc_lease_table() before opinfo_add()

so add_lease_global_list() becomes infallible after publication.

Keep the original m_op_list publication order (opinfo_add before

lease list) so concurrent opens via same_client_has_lease() and

opinfo_get_list() still see the in-flight grant.

Use opinfo_put() instead of __free_opinfo() on err_out so that

the RCU-deferred free path is used.

This also requires splitting add_lease_global_list() to take a

preallocated lease_table and changing its return type from int to void,

since it can no longer fail.

Verified Sources

References

https://git.kernel.org/stable/c/48623ec358c1c600fa1e38368746f933e0f1a617
https://git.kernel.org/stable/c/6d7e5a918c1d0aad06db0e17677b66fc9a471021
https://git.kernel.org/stable/c/7de55bba69cbf0f9280daaea385daf08bc076121
https://git.kernel.org/stable/c/9e785f004cbc56390479b77375726ea9b0d1a8a6
https://git.kernel.org/stable/c/a5c6f6d6ceefed2d5210ee420fb75f8362461f46

_Validated by the Lyrie Threat Intelligence Pipeline — 3 independent sources confirmed before publication. No speculation._

Lyrie Verdict

A vulnerability of this severity is exactly what Lyrie's anti-rogue-AI defense is built for: continuous, autonomous monitoring that doesn't wait for human reaction time.

#critical