CVE-2026-45078 Details
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.
A denial-of-service vulnerability has been identified in Matrix Synapse versions prior to 1.152.1. This issue allows local authenticated users to consume excessive CPU resources, causing other requests to fail and denying service to other users. Homeservers that trust all local users are not vulnerable.
Users can update to Synapse version 1.152.1 or later to address this vulnerability. If Synapse is behind a reverse proxy, the proxy can be configured to limit user request rates, mitigating the attack.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed May 29, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/element-hq/synapse/security/advisories/GHSA-8q93-326v-3m7g | [email protected] | MitigationVendor Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-770 | Allocation of Resources Without Limits or Throttling | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| element synapse | < 1.152.1 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 3, 2026 | Initial Analysis | [email protected] |
| May 28, 2026 | New CVE Received | [email protected] |