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.
Published: 2026-04-01
Score: 8.2 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

Vendor Workaround

To mitigate this vulnerability, restrict network access to the Corosync service on UDP port 5405 to only trusted hosts or networks. If Corosync is not required, consider disabling the service. Example firewall rule to restrict access to a trusted network (replace <TRUSTED_NETWORK> with your network): `firewall-cmd --permanent --add-rich-rule='rule family="ipv4" port port="5405" protocol="udp" source address="<TRUSTED_NETWORK>" accept'` `firewall-cmd --reload` To disable the Corosync service: `systemctl stop corosync` `systemctl disable corosync` Note that restricting access may impact cluster communication, and disabling the service will prevent cluster operation. A restart of the Corosync service or a system reboot may be required for changes to take full effect.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

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'}


Subscriptions

Redhat Enterprise Linux Openshift
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-04-01T20:29:55.615Z

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 : Undergoing Analysis

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

Modified: 2026-04-01T14:23:37.727

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

No data.

Weaknesses