CVE-2026-45078

Synapse CPU starvation (Denial of Service)

State: Published
Severity: 6.8 Medium
Published: May 28, 2026
Updated: May 29, 2026
Reserved: May 8, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	6.8 Medium	CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-770 Allocation of Resources Without Limits or Throttling

Affected Products

Product	Versions
synapseelement-hq	< 1.152.1Affected

References

https://github.com/element-hq/synapse/security/advisories/GHSA-8q93-326v-3m7g

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