CVE-2026-45955 md/md-llbitmap: fix percpu_ref not resurrected on suspend timeout

What is CVE-2026-45955?

CVE-2026-45955 is a high-severity denial of service vulnerability in Linux kernel, published on 27 May 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:

md/md-llbitmap: fix percpu_ref not resurrected on suspend timeout

When llbitmap_suspend_timeout() times out waiting for percpu_ref to become zero, it returns -ETIMEDOUT without resurrecting the percpu_ref. The caller (md_llbitmap_daemon_fn) then continues to the next page without calling llbitmap_resume(), leaving the percpu_ref in a killed state permanently.

Fix this by resurrecting the percpu_ref before returning the error, ensuring the page control structure remains usable for subsequent operations.

Weakness: CWE-404

Which versions are affected by CVE-2026-45955?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-45955?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-45955 being exploited?

There is no known exploitation of CVE-2026-45955 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-2026-45955, DEBIAN-CVE-2026-45955, GHSA-7293-q55v-843q, UBUNTU-CVE-2026-45955.