CVE-2026-45076Medium▾ SunlitSynapse pagination Denial of Service
▾ Sunlit zone — Low / medium · no exploitation signal
impact 27.5 · likelihood 0.1 · exploitation 0
Need a working PoC? Pro members can cast a request and our team develops one — it lands right here.
Exploit-prediction probability, daily snapshots since Sep 12.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
0.4%
In federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients.
Clients could therefore fail to display room history.
Update to Synapse 1.152.1 or later.
There are no known workarounds for this issue.
If you have any questions or comments about this advisory, please email us at security at element.io.
matrix-synapse < 1.152.1Upgrade to a patched release:
matrix-synapse 1.152.1Connected by shared product, vendor, weakness, or advisory.
CVE-2026-45078Medium· 5.5Synapse CPU starvation (Denial of Service)
CVE-2024-31208Medium· 6.5Synapse V2 state resolution weakness allows Denial of Service (DoS)
CVE-2024-53863HighSynapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders
CVE-2025-30355High· 7.1Synapse vulnerable to federation denial of service via malformed events
CVE-2024-52805HighSynapse allows unsupported content types to lead to memory exhaustion
CVE-2025-61672MediumSynapse's invalid device keys degrade federation functionality