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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — |
| Red Hat | Red Hat OpenShift Container Platform 5 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | corosync | No fix yet | — |
| Debian 13 | corosync | No fix yet | — |
| Debian 12 | corosync | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | corosync | No fix yet | — |
| Ubuntu 26.04 LTS | corosync | No fix yet | — |
| Ubuntu 24.04 LTS | corosync | No fix yet | — |
| Ubuntu 22.04 LTS | corosync | No fix yet | — |
| Ubuntu 20.04 LTS | corosync | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | corosync | No fix yet | — |
| Ubuntu 16.04 LTS | corosync | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | corosync | 2.4.6-150300.12.19.1 | SUSE-SU-2026:4202-1 |
| SLES 15 SP6 | corosync | 2.4.6-150300.12.19.1 | SUSE-SU-2026:4202-1 |
| SLES 15 SP5 | corosync | 2.4.6-150300.12.19.1 | SUSE-SU-2026:4202-1 |
| SLES 15 SP4 | corosync | 2.4.6-150300.12.19.1 | SUSE-SU-2026:4202-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 16.0 | corosync | 3.1.9-160000.4.1 | SUSE-SU-2026:23850-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | corosync | 3.1.10-5.1 | openSUSE-SU-2026:11715-1 |
| openSUSE Leap 16.0 | corosync | 3.1.9-160000.4.1 | openSUSE-SU-2026:21887-1 |
Advisories 4
- SUSE-SU-2026:23850-1 Security update for corosync SUSE / openSUSE Security Updates · Sep 27, 2026
- openSUSE-SU-2026:21887-1 Security update for corosync SUSE / openSUSE Security Updates · Sep 25, 2026
- SUSE-SU-2026:4202-1 Security update for corosync SUSE / openSUSE Security Updates · Sep 16, 2026
- openSUSE-SU-2026:11715-1 corosync-3.1.10-5.1 on GA media SUSE / openSUSE Security Updates · Sep 9, 2026
References
- https://access.redhat.com/security/cve/CVE-2026-81666 vdb-entry
- RHBZ#2524923 issue-tracking