- 4.9MediumCVSS base score
- 1.4%Exploitation in 30 daysEPSS · top 27% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. Prior to version 1.94.0, a malicious server ACL event can impact performance temporarily or permanently leading to a persistent denial of service. Homeservers running on a closed federation (which presumably do not need to use server ACLs) are not affected. Server administrators are advised to upgrade to Synapse 1.94.0 or later. As a workaround, rooms with malicious server ACL events can be purged and blocked using the admin API.
Timeline
ID reserved
By GitHub_M
- 6 days later
· 6 days later
Published
- 16 months later
· 16 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium4.9 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | Medium4.9 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 1.4% · top 27% of all CVEs (11 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.9.
Affected products
- affected < 1.94.0
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPImatrix-synapseGHSA-5chr-wjw5-3gq4 (opens in a new tab)
References
References7
- https://github.com/matrix-org/synapse/security/advisories/GHSA-5chr-wjw5-3gq4 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/matrix-org/synapse/pull/16360 (opens in a new tab)x_refsource_MISCx_transferred
- https://matrix-org.github.io/synapse/latest/admin_api/rooms.html#version-2-new-version (opens in a new tab)x_refsource_MISCx_transferred
- https://lists.fedoraproject.org/archives/list/[email protected]/message/WRO4MPQ6HOXIUZM6RJP6VTCTMV7RD2T3/ (opens in a new tab)x_transferred
- https://lists.fedoraproject.org/archives/list/[email protected]/message/KEVRB4MG5UXQ5RLZHSUJXM5GWEBYYS5B/ (opens in a new tab)x_transferred
- https://lists.fedoraproject.org/archives/list/[email protected]/message/N6P4QULVUE254WI7XF2LWWOGHCYVFXFY/ (opens in a new tab)x_transferred
- https://security.gentoo.org/glsa/202401-12 (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2023-0135 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-5chr-wjw5-3gq4 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2023-45129)Record last updated .