9.8
CRITICAL CVSS 3.1
CVE-2026-89494
ocfs2: validate lengths in dlm_mig_lockres_handler
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.

INFO

Published Date :

Sept. 11, 2026, 8:19 p.m.

Last Modified :

Sept. 14, 2026, 1:19 p.m.

Remotely Exploit :

Yes !

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products

The following products are affected by CVE-2026-89494 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
Validate lengths and data in DLM messages to prevent out-of-bounds reads and writes.
  • Validate num_locks and lockname_len from peer messages.
  • Ensure message payload matches claimed lock entries.
  • Reject messages with invalid length fields.
  • Apply the fix to dlm_process_recovery_data and dlm_init_lockres.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-89494 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-89494 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-89494 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-89494 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Sep. 14, 2026

    Action Type Old Value New Value
    Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89494.json">CVE-2026-89494</a>
    Added Reference https://git.kernel.org/stable/c/0e999d56917f861f97adb961617b1828c9eb4733
    Added Reference https://git.kernel.org/stable/c/4a5798253212093b9ff7d90c6cfbe348bcda1594
    Added Reference https://git.kernel.org/stable/c/77686fa5bba135252d348e2dacf481fc19f60c41
    Added Reference https://git.kernel.org/stable/c/dce05b17db862f47ff60614017abe639b2e71cad
  • CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Sep. 13, 2026

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Sep. 11, 2026

    Action Type Old Value New Value
    Added 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.
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89494.json">CVE-2026-89494</a>
    Added Reference https://git.kernel.org/stable/c/50c4cc9183e11f83427efbf770f54851f4471c02
    Added Reference https://git.kernel.org/stable/c/a8facb1670b4a0612183198e758d9539ef628ed9
    Added Reference https://git.kernel.org/stable/c/b54e03d9b3697d25f4a0063cf717d459c5e3ad94
    Added Reference https://git.kernel.org/stable/c/f33041906885f96e190cde54e61ddc69de39e3ee
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.