CVE-2026-45076
published 2026-05-28CVE-2026-45076: 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…
PriorityP410low2.7CVSS 3.1
AVNACLPRHUINSUCNINAL
EPSS
0.37%
29.2th percentile
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 vulnerability is fixed in 1.152.1.
Affected
3 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | matrix-synapse | >= 0 < 1.152.1 | 1.152.1 |
| element-hq | synapse | < 1.152.1 | 1.152.1 |
| element | synapse | < 1.152.1 | 1.152.1 |
CVSS provenance
nvdv3.12.7LOWCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L
nvdv4.05.1MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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VulDB
element-hq synapse up to 1.152.0 denial of service (GHSA-6qf2-7x63-mm6v / Nessus ID 318084)
vuldb·2026-06-07·CVSS 2.7
CVE-2026-45076 [LOW] element-hq synapse up to 1.152.0 denial of service (GHSA-6qf2-7x63-mm6v / Nessus ID 318084)
A vulnerability classified as problematic was found in element-hq synapse up to 1.152.0. Impacted is an unknown function. Such manipulation leads to denial of service.
This vulnerability is referenced as CVE-2026-45076. It is possible to launch the attack remotely. No exploit is available.
Upgrading the affected component is advised.
GHSA
Synapse pagination Denial of Service
ghsa·2026-05-14
CVE-2026-45076 [MEDIUM] CWE-20 Synapse pagination Denial of Service
Synapse pagination Denial of Service
### Impact
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.
### Patches
Update to Synapse 1.152.1 or later.
### Workarounds
There are no known workarounds for this issue.
### Identifiers
- ELEMENTSEC-2025-1636
### For more information
If you have any questions or comments about this advisory, please email us at [security at element.io](mailto:[email protected]).
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-45076 matrix-synapse: Synapse pagination denial of service [fedora-all]
bugzilla·2026-06-08·CVSS 2.7
CVE-2026-45076 [LOW] CVE-2026-45076 matrix-synapse: Synapse pagination denial of service [fedora-all]
CVE-2026-45076 matrix-synapse: Synapse pagination denial of service [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-45076 synapse: Synapse pagination denial of service [fedora-all]
bugzilla·2026-06-08·CVSS 2.7
CVE-2026-45076 [LOW] CVE-2026-45076 synapse: Synapse pagination denial of service [fedora-all]
CVE-2026-45076 synapse: Synapse pagination denial of service [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-45076 Synapse: Synapse pagination denial of service
bugzilla·2026-05-28·CVSS 2.7
CVE-2026-45076 [LOW] CVE-2026-45076 Synapse: Synapse pagination denial of service
CVE-2026-45076 Synapse: Synapse pagination denial of service
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 vulnerability is fixed in 1.152.1.
2026-05-28
Published