CVE-2026-43309 md raid: fix hang when stopping arrays with metadata through dm-raid

What is CVE-2026-43309?

CVE-2026-43309 is a medium-severity denial of service vulnerability in Linux kernel, published on 8 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 raid: fix hang when stopping arrays with metadata through dm-raid

When using device-mapper's dm-raid target, stopping a RAID array can cause the system to hang under specific conditions.

This occurs when:

- A dm-raid managed device tree is suspended from top to bottom (the top-level RAID device is suspended first, followed by its underlying metadata and data devices)

- The top-level RAID device is then removed

Removing the top-level device triggers a hang in the following sequence: the dm-raid destructor calls md_stop(), which tries to flush the write-intent bitmap by writing to the metadata sub-devices. However, these devices are already suspended, making them unable to complete the write-intent operations and causing an indefinite block.

Fix:

- Prevent bitmap flushing when md_stop() is called from dm-raid destructor context and avoid a quiescing/unquescing cycle which could also cause I/O

- Still allow write-intent bitmap flushing when called from dm-raid suspend context

This ensures that RAID array teardown can complete successfully even when the underlying devices are in a suspended state.

This second patch uses md_is_rdwr() to distinguish between suspend and destructor paths as elaborated on above.

Which versions are affected by CVE-2026-43309?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-43309?

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-2026-43309 being exploited?

There is no known exploitation of CVE-2026-43309 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 AZL-86124, BELL-CVE-2026-43309, DEBIAN-CVE-2026-43309, GHSA-v56g-44rc-67wq, ROOT-OS-DEBIAN-11-CVE-2026-43309, ROOT-OS-DEBIAN-12-CVE-2026-43309 and 4 more.