Bug 2482770 (CVE-2026-45078)

Summary: CVE-2026-45078 synapse: Synapse: Denial of Service due to resource exhaustion by authenticated users
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Synapse, an open source Matrix homeserver implementation. Local authenticated users can exploit this vulnerability to consume excessive CPU resources, causing the server to become unresponsive and denying service to other users. This can lead to a complete Denial of Service (DoS) for legitimate users of the homeserver.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2489275, 2489274    
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Description OSIDB Bzimport 2026-05-28 17:01:53 UTC
Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1.