CVE-2026-72440 md/raid1: fix writes_pending and barrier reference leaks on write failures
A bug in the Linux kernel's RAID1 driver causes resource leaks on write failures, potentially leading to a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72440?
CVE-2026-72440 is a high-severity denial of service vulnerability in Linux, published on 15 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
md/raid1: fix writes_pending and barrier reference leaks on write failures
raid1_make_request() acquires a writes_pending reference with md_write_start() before calling raid1_write_request(). Several failure paths in raid1_write_request() complete the bio and return without reaching the normal write completion path, causing the corresponding md_write_end() to be skipped.
Make raid1_write_request() return a status indicating whether the write request was successfully queued. This allows raid1_make_request() to call md_write_end() when raid1_write_request() fails.
Additionally, if wait_blocked_rdev() fails after wait_barrier() succeeds, the associated barrier reference is not released.
Call allow_barrier() before returning from that path to keep the barrier accounting balanced.
Which versions are affected by CVE-2026-72440?
How do I fix CVE-2026-72440?
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-2026-72440 being exploited?
There is no known exploitation of CVE-2026-72440 in the wild and no public exploit code.
Sources
Also known as AZL-96588, BELL-CVE-2026-72440, DEBIAN-CVE-2026-72440, GHSA-jh9h-wfxq-pfm4, UBUNTU-CVE-2026-72440.