Bug 2453814 (CVE-2026-35092)

Summary: CVE-2026-35092 corosync: Corosync: Denial of Service via integer overflow in join message validation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: security-response-team
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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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.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2453821    
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Description OSIDB Bzimport 2026-04-01 11:32:27 UTC 
Integer overflow (wraparound) vulnerability in Corosync’s join message sanity validation in exec/totemsrp.c. The flaw is in check_memb_join_sanity(), where proc_list_entries and failed_list_entries are attacker-controlled 32-bit unsigned values received from the network and are added together before being promoted to size_t. This allows the addition (proc_list_entries + failed_list_entries) to wrap around in 32-bit arithmetic (e.g., 0x80000000 + 0x80000000 = 0), causing required_len to be calculated too small and allowing a short packet to pass validation. As a result, Corosync proceeds with processing malformed input that should have been rejected, which can be exploited remotely without authentication in totemudp/totemudpu mode via crafted UDP packets to crash the service, resulting in a denial of service.