Cloudanix VulnDB

CVE-2026-80820

None

CVSS

—

EPSS

0.2%

Published

Sep 4, 2026

CISA due date

—

Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in Linux file-system checking could let a specially made disk image freeze the checker forever and tie up the system.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Denial Of Service
Component
OS kernel
Class
Denial of service
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Online XFS scrub can enter a livelock when traversing an unlinked inode list that forms a cycle instead of terminating.

Why it matters to the business

Filesystem maintenance operations on XFS volumes may hang indefinitely, causing extended downtime for storage maintenance and potential unavailability of data services on Linux systems.

How an attack unfolds

An attacker crafts or supplies a malicious XFS filesystem image containing a circular unlinked inode list; when the victim runs online fsck or scrub against that image the kernel enters an infinite loop and the process never completes.

How to fix it

Apply the upstream kernel patch that adds cycle detection via bitmap during unlinked-list traversal in XFS scrub; rebuild and deploy the fixed kernel on all affected systems.

How to confirm the fix worked

Confirm the running kernel contains the commit that introduces bitmap-based cycle detection in xfs_scrub; test scrub on a synthetic cyclic unlinked list to verify it terminates instead of hanging.

Typical attack path

  1. Prepare or obtain an XFS filesystem image with a deliberately circular unlinked inode list
  2. Mount the image or cause the target system to run xfs_scrub or online fsck against it
  3. Trigger the scrub operation, inducing the livelock that consumes CPU and prevents completion
  4. Repeat or sustain the condition to maintain denial of service on storage maintenance tasks

How to detect it

Look in system logs for xfs_scrub or fsck processes that remain in running state for abnormally long periods with high CPU usage on XFS volumes; correlate with attempts to mount or check untrusted filesystem images.

What your security team should do

  • Prioritize patching Linux kernels that use XFS and perform online scrubbing
  • Restrict untrusted XFS images from being mounted or scrubbed on production systems until patched
  • Monitor kernel update channels for the specific XFS scrub fix and schedule rollout within normal change windows given low EPSS

The record

In the Linux kernel, the following vulnerability has been resolved: xfs: don't livelock in scrub on a circular unlinked list LOLLM points out that online fsck can livelock if an unlinked inode list contains a loop. Use a bitmap to detect cycles.

Affected packages

Ecosystem Package Introduced Fixed