# CVE-2026-81665

## Summary

- **CVE ID:** CVE-2026-81665
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** CWE-122
- **Published:** Sep 4, 2026
- **Last Modified:** Sep 4, 2026

## Description

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.

## Affected Products

No affected products listed.

## References

- [CNA](https://access.redhat.com/security/cve/CVE-2026-81665)
- [CNA](https://bugzilla.redhat.com/show_bug.cgi?id=2524910)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.21%
- **EPSS Percentile:** 11.5

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._