CVE-2026-81666 Integer overflow in Red Hat Enterprise Linux 10
An integer overflow in Corosync allows remote attackers to crash cluster nodes on 32-bit systems via crafted network packets, causing denial of service.
- 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-2026-81666?
CVE-2026-81666 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 4 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
An integer overflow was found in Corosync's handling of membership commit token messages. The length-validation check for these messages can be bypassed on 32-bit systems due to an integer overflow in the calculation of the expected message length, allowing a crafted network packet to trigger an out-of-bounds memory access that crashes the Corosync daemon. This results in a denial of service for the affected cluster node. The overflow does not occur on 64-bit systems, where the length calculation is correctly performed in 64-bit arithmetic.
Weakness: CWE-190
Which versions are affected by CVE-2026-81666?
How do I fix CVE-2026-81666?
Apply the vendor's patch.
Is CVE-2026-81666 being exploited?
There is no known exploitation of CVE-2026-81666 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-81666, GHSA-8297-6g53-8gp5, UBUNTU-CVE-2026-81666.