Critical severity · published Sep 11, 2026
CVE-2026-89494
ocfs2: validate lengths in dlm_mig_lockres_handler
9.8
CVSS
0.7%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate lengths in dlm_mig_lockres_handler A node receiving a DLM_MIG_LOCKRES message trusts several fields of the peer-supplied dlm_migratable_lockres without validation. num_locks and lockname_len are bounded only on the sending side, and the message is never checked to actually carry num_locks migratable_lock entries. As a result dlm_process_recovery_data() walks mres->ml[0..num_locks) past the kmalloc(data_len) copy of the message (an out-of-bounds read that ends in a BUG_ON panic), and dlm_init_lockres() copies lockname_len bytes into the fixed 32-byte o2dlm_lockname slab object (a heap out-of-bounds write). Both are reachable by any node in the domain. Validate these fields right after dlm_grab(), before anything uses them -- including the not-joined error path, which already prints mres->lockname with the unbounded lockname_len as a %.*s precision. Reject the message unless lockname_len <= DLM_LOCKID_NAME_MAX, num_locks <= DLM_MAX_MIGRATABLE_LOCKS (the bound the sender already asserts), and the payload is large enough to hold the claimed locks. Conforming recovery and migration messages are unaffected.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 53% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux · Linux
6714d8e86bf443f6f7af50f9d432025649f091f5 before 4a5798253212093b9ff7d90c6cfbe348bcda1594; 6714d8e86bf443f6f7af50f9d432025649f091f5 before dce05b17db862f47ff60614017abe639b2e71cad; 6714d8e86bf443f6f7af50f9d432025649f091f5 before 0e999d56917f861f97adb961617b1828c9eb4733; 6714d8e86bf443f6f7af50f9d432025649f091f5 before 77686fa5bba135252d348e2dacf481fc19f60c41; 6714d8e86bf443f6f7af50f9d432025649f091f5 before f33041906885f96e190cde54e61ddc69de39e3ee; 6714d8e86bf443f6f7af50f9d432025649f091f5 before 50c4cc9183e11f83427efbf770f54851f4471c02; +3 more · source: vendor