Corosync: corosync: denial of service via integer overflow in join message validation

Summary

CVE	CVE-2026-35092
State	PUBLISHED
Assigner	redhat
Source Priority	CVE Program / NVD first with legacy fallback
Published	2026-04-01 14:16:57 UTC
Updated	2026-05-06 21:16:00 UTC
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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.002200000 probability, percentile 0.443530000 (date 2026-05-05)

Problem Types: CWE-190 | CWE-190 Integer Overflow or Wraparound

Version	Source	Type	Score	Severity	Vector
3.1	[email protected]	Secondary	7.5	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`
3.1	CNA	CVSS	7.5	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`

CVSS v3.1 Breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

Type	Vendor	Product	Version	Update	Edition	Language
Application	Corosync	Corosync	-	All	All	All
Operating System	Redhat	Enterprise Linux	10.0	All	All	All
Operating System	Redhat	Enterprise Linux	7.0	All	All	All
Operating System	Redhat	Enterprise Linux	8.0	All	All	All
Operating System	Redhat	Enterprise Linux	9.0	All	All	All
Application	Redhat	Openshift	4.0	All	All	All

Vendor Declared Affected Products

Source	Vendor	Product	Version	Platforms
CNA	Red Hat	Red Hat Enterprise Linux 10	unaffected 0:3.1.9-2.el10_1.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 10.0 Extended Update Support	unaffected 0:3.1.9-1.el10_0.2 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 8	unaffected 0:3.1.8-1.el8_10.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	unaffected 0:3.1.0-3.el8_4.2 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On	unaffected 0:3.1.0-3.el8_4.2 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support	unaffected 0:3.1.5-2.el8_6.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 8.6 Telecommunications Update Service	unaffected 0:3.1.5-2.el8_6.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 8.6 Update Services For SAP Solutions	unaffected 0:3.1.5-2.el8_6.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 8.8 Telecommunications Update Service	unaffected 0:3.1.7-1.el8_8.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 8.8 Update Services For SAP Solutions	unaffected 0:3.1.7-1.el8_8.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 9	unaffected 0:3.1.9-2.el9_7.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 9.0 Update Services For SAP Solutions	unaffected 0:3.1.5-3.el9_0.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 9.2 Update Services For SAP Solutions	unaffected 0:3.1.7-1.el9_2.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 9.4 Extended Update Support	unaffected 0:3.1.8-1.el9_4.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 9.6 Extended Update Support	unaffected 0:3.1.9-2.el9_6.1 * rpm	Not specified
CNA	Red Hat	Red Hat Enterprise Linux 7	Not specified	Not specified
CNA	Red Hat	Red Hat OpenShift Container Platform 4	Not specified	Not specified

References

Reference	Source	Link	Tags
access.redhat.com/errata/RHSA-2026:14205	[email protected]	access.redhat.com
access.redhat.com/errata/RHSA-2026:14212	[email protected]	access.redhat.com
access.redhat.com/errata/RHSA-2026:14213	[email protected]	access.redhat.com
access.redhat.com/errata/RHSA-2026:13673	[email protected]	access.redhat.com
access.redhat.com/errata/RHSA-2026:14210	[email protected]	access.redhat.com
access.redhat.com/errata/RHSA-2026:13644	[email protected]	access.redhat.com
bugzilla.redhat.com/show_bug.cgi	[email protected]	bugzilla.redhat.com	Exploit, Third Party Advisory
access.redhat.com/errata/RHSA-2026:14211	[email protected]	access.redhat.com
access.redhat.com/security/cve/CVE-2026-35092	[email protected]	access.redhat.com	Third Party Advisory, VDB Entry
access.redhat.com/errata/RHSA-2026:14216	[email protected]	access.redhat.com
bugzilla.redhat.com/show_bug.cgi	[email protected]	bugzilla.redhat.com	Issue Tracking, Third Party Advisory
access.redhat.com/errata/RHSA-2026:14215	[email protected]	access.redhat.com
access.redhat.com/errata/RHSA-2026:13657	[email protected]	access.redhat.com
access.redhat.com/errata/RHSA-2026:14214	[email protected]	access.redhat.com
CVE Program record	CVE.ORG	www.cve.org	canonical
NVD vulnerability detail	NVD	nvd.nist.gov	canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Red Hat would like to thank Sebastián Alba Vives for reporting this issue. (en)

Additional Advisory Data

Source	Time	Event
CNA	2026-04-01T11:32:04.388Z	Reported to Red Hat.
CNA	2026-04-01T11:48:22.309Z	Made public.

Workarounds

CNA: Restrict network access to Corosync cluster communication ports. Configure firewall rules to limit incoming UDP traffic to the Corosync service (default port 5405) to only trusted hosts within the cluster. This will prevent unauthenticated remote attackers from sending crafted packets to exploit the vulnerability. A service restart may be required for firewall changes to take full effect.

There are currently no legacy QID mappings associated with this CVE.