Independent & educational platform Not a government body. No link or affiliation with any government organisation. Made for learning only. Test only systems you own or are authorised to test. Become a Partner or Sponsor → Full disclaimer

CVE-2026-81665

high

A heap-based buffer overflow was found in Corosync's Totem Process Group (totempg) message reassembly.

A heap-based buffer overflow was found in Corosync's Totem Process Group (totempg) message reassembly. When processing fragmented multicast messages, the buffer used to reassemble fragments lacks a runtime bounds check in release builds. A network-adjacent attacker able to send crafted multicast protocol messages to the cluster could cause a heap buffer overflow with attacker-controlled data. This can crash the Corosync daemon, causing a denial of service to the entire cluster, and may potentially allow further exploitation given sufficient heap-corruption control.

CVSS
7.5
7.5 (CVSS v3.1)
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity source: NVD CVSS v3.1 (secalert@redhat.com)
Timeline (UTC)
Published: 2026-09-04 09:17
Modified: 2026-10-21 21:19
NVD status: Awaiting Analysis
Last synced 1 day ago
Verified against the source API 2026-10-27 06:50 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

Not reported by the source (unknown — not "none").

Weakness classification (CWE)

CWE-122

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

No vendor advisory or patch reference tagged by NVD. Check the references below.

References

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 06:50 UTC · record ↗

Learn the basics

Understanding CVEs and CVSS Scores