A flaw was found in Corosync. A remote unauthenticated attacker can exploit a wrong return value vulnerability in the Corosync membership commit token sanity check by sending a specially crafted User Datagram Protocol (UDP) packet. This can lead to an out-of-bounds read, causing a denial of service (DoS) and potentially disclosing limited memory contents. This vulnerability affects Corosync when running in totemudp/totemudpu mode, which is the default configuration.

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Fixes

Solution

No solution given by the vendor.


Workaround

Systems using totemudp or totemudpu should migrate to the supported knet transport and enable encryption. Disabling the Corosync service is a valid workaround if clustering is not required, but for active clusters, enabling encryption via knet is the preferred and recommended approach.

History

Tue, 07 Apr 2026 18:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:a:corosync:corosync:-:*:*:*:*:*:*:*
cpe:2.3:a:redhat:openshift:4.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*

Fri, 03 Apr 2026 10:15:00 +0000

Type Values Removed Values Added
First Time appeared Corosync
Corosync corosync
Redhat openshift Container Platform
Vendors & Products Corosync
Corosync corosync
Redhat openshift Container Platform

Thu, 02 Apr 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Wed, 01 Apr 2026 23:45:00 +0000

Type Values Removed Values Added
Description A flaw was found in Corosync. A remote unauthenticated attacker can exploit a wrong return value vulnerability in the Corosync membership commit token sanity check by sending a specially crafted User Datagram Protocol (UDP) packet. This can lead to an out-of-bounds read, causing a denial of service (DoS) and potentially disclosing limited memory contents. This vulnerability affects Corosync when running in totemudp/totemudpu mode, which is the default configuration.
Title Corosync: corosync: denial of service and information disclosure via crafted udp packet
First Time appeared Redhat
Redhat enterprise Linux
Redhat openshift
Weaknesses CWE-253
CPEs cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat openshift
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-04-06T07:32:08.097Z

Reserved: 2026-04-01T11:35:23.145Z

Link: CVE-2026-35091

cve-icon Vulnrichment

Updated: 2026-04-01T20:29:29.178Z

cve-icon NVD

Status : Analyzed

Published: 2026-04-01T14:16:57.040

Modified: 2026-04-07T16:34:38.267

Link: CVE-2026-35091

cve-icon Redhat

Severity : Important

Publid Date: 2026-04-01T11:48:13Z

Links: CVE-2026-35091 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-08T19:59:50Z

Weaknesses