Is there a public exploit for CVE-2026-81666?

No public exploit for CVE-2026-81666 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-81666?

CVE-2026-81666 scores CVSS 6.5 (v3.1), rated medium. EPSS puts the chance of exploitation in the next 30 days at 0.25%.

6.5 Medium

An integer overflow was found in Corosync's handling of membership commit token messages.

CVE-2026-81666

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.

Assessment

CVSS: 6.5 (v3.1)
Severity: Medium
EPSS: 0.25% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 4 September 2026
Last updated: 3 November 2026
Assigner: redhat

CVSS vectorCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

At the source

EUVD (ENISA)

References

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