Is matrix-synapse affected by CVE-2026-45076?

PyPI matrix-synapse is affected in <1.152.1.

Is CVE-2026-45076 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.4%.

low

CVE-2026-45076

Q: Is CVE-2026-45076 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.4%.

PyPI · matrix-synapse

Summary

Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, 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. This vulnerabilit

Severity: low
EPSS: 0.4% (p28)
Also known as: GHSA-6qf2-7x63-mm6v, PYSEC-2026-194
Published: 2026-05-28

References

https://github.com/element-hq/synapse/security/advisories/GHSA-6qf2-7x63-mm6v

Related advisories

CVE-2025-30355 — high · PyPI/matrix-synapse
CVE-2024-53863 — high · PyPI/matrix-synapse
CVE-2024-52815 — high · PyPI/matrix-synapse
CVE-2024-52805 — high · PyPI/matrix-synapse
CVE-2024-37302 — high · PyPI/matrix-synapse
CVE-2026-45078 — medium · PyPI/matrix-synapse
CVE-2025-61672 — medium · PyPI/matrix-synapse
CVE-2024-53867 — medium · PyPI/matrix-synapse

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Sources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.