CVE-2026-72437 md/raid1: free r1_bio when REQ_NOWAIT is set and read would block on retry
A memory leak in the Linux kernel RAID1 driver can lead to resource exhaustion and denial of service when handling blocked read retries.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72437?
CVE-2026-72437 is a memory corruption vulnerability in Linux, published on 15 Aug 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/raid1: free r1_bio when REQ_NOWAIT is set and read would block on retry
When a read is retried, raid1_read_request() may be called with a pre-allocated r1_bio. If wait_read_barrier() fails for a REQ_NOWAIT read, the bio is completed and the function returns immediately. In this case the existing r1_bio is leaked.
This fixes a leak of pre-allocated r1_bio structures for retried reads.
Which versions are affected by CVE-2026-72437?
How do I fix CVE-2026-72437?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-72437 being exploited?
There is no known exploitation of CVE-2026-72437 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72437, DEBIAN-CVE-2026-72437, GHSA-hcmp-m525-ffjq, UBUNTU-CVE-2026-72437.