CVE-2026-31556 xfs: scrub: unlock dquot before early return in quota scrub

What is CVE-2026-31556?

CVE-2026-31556 is a medium-severity vulnerability in Linux kernel, published on 24 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

xfs: scrub: unlock dquot before early return in quota scrub

xchk_quota_item can return early after calling xchk_fblock_process_error. When that helper returns false, the function returned immediately without dropping dq->q_qlock, which can leave the dquot lock held and risk lock leaks or deadlocks in later quota operations.

Fix this by unlocking dq->q_qlock before the early return.

Which versions are affected by CVE-2026-31556?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-31556?

Apply the vendor's patch.

Is CVE-2026-31556 being exploited?

There is no known exploitation of CVE-2026-31556 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-31556, DEBIAN-CVE-2026-31556, GHSA-v4f5-4j9w-9f24, ROOT-OS-UBUNTU-2404-CVE-2026-31556, UBUNTU-CVE-2026-31556.