Resource exhaustion in Matrix Synapse

CVE-2023-45129

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.9 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.012 (66.0th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 66th percentile — 66.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2023-45129: held from 0.012 to 0.012.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2023-45129?
CVE-2023-45129 is a medium-severity vulnerability in Matrix Synapse, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 4.9/10. Published 2023-10-10.
How severe is CVE-2023-45129?
Medium severity. CVSS v3 base score is 4.9 out of 10.