CVE-2026-45078: CWE-770: Allocation of Resources Without Limits or Throttling in element-hq synapse
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.
AI Analysis
Technical Summary
This vulnerability, classified as CWE-770 (Allocation of Resources Without Limits or Throttling), affects Synapse versions before 1.152.1. It allows local authenticated users to consume excessive CPU resources, starving other requests and causing service denial. The CVSS 4.0 base score is 6.8, reflecting a medium severity with local attack vector and low attack complexity. The vulnerability does not require user interaction or privileges beyond authentication and does not impact confidentiality, integrity, or availability beyond denial of service. The issue is fixed in Synapse 1.152.1.
Potential Impact
Exploitation allows local authenticated users to cause denial of service by exhausting CPU resources, preventing other users' requests from being processed. There is no indication of data compromise or privilege escalation. No known exploits are reported in the wild.
Mitigation Recommendations
Upgrade Synapse to version 1.152.1 or later, where this vulnerability is fixed. Since this is an open source product and not a cloud service, applying the official patch is required to remediate the issue. Patch status is confirmed by the vendor advisory stating the fix is included in version 1.152.1.
CVE-2026-45078: CWE-770: Allocation of Resources Without Limits or Throttling in element-hq synapse
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.
CVSS v4.0
Score 6.8medium
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability, classified as CWE-770 (Allocation of Resources Without Limits or Throttling), affects Synapse versions before 1.152.1. It allows local authenticated users to consume excessive CPU resources, starving other requests and causing service denial. The CVSS 4.0 base score is 6.8, reflecting a medium severity with local attack vector and low attack complexity. The vulnerability does not require user interaction or privileges beyond authentication and does not impact confidentiality, integrity, or availability beyond denial of service. The issue is fixed in Synapse 1.152.1.
Potential Impact
Exploitation allows local authenticated users to cause denial of service by exhausting CPU resources, preventing other users' requests from being processed. There is no indication of data compromise or privilege escalation. No known exploits are reported in the wild.
Mitigation Recommendations
Upgrade Synapse to version 1.152.1 or later, where this vulnerability is fixed. Since this is an open source product and not a cloud service, applying the official patch is required to remediate the issue. Patch status is confirmed by the vendor advisory stating the fix is included in version 1.152.1.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-08T18:45:10.097Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a1871ece29bf47b50124587
Added to database: 5/28/2026, 4:48:44 PM
Last enriched: 5/28/2026, 5:04:54 PM
Last updated: 5/29/2026, 8:20:49 AM
Views: 7
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