Improper input validation in Matrix Synapse
CVE-2023-32323
Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. A malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y. Synapse instances with federation disabled are not affected. In versions of Synapse up to and including 1.73, Synapse did not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event. Synapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.0 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.010 (60.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 60.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000
Affected products
- Matrix Synapse
- Matrix-Org Synapse — versions < 1.74.0
Weakness classification (CWE)
References
- github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr (Mitigation, Vendor Advisory)
- github.com/matrix-org/synapse/issues/14492 (Exploit, Issue Tracking)
- github.com/matrix-org/synapse/pull/14642 (Patch)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/…
Frequently asked questions
- What is CVE-2023-32323?
- CVE-2023-32323 is a medium-severity vulnerability in Matrix Synapse, classified under Improper Input Validation. CVSS score: 5.0/10. Published 2023-05-26.
- How severe is CVE-2023-32323?
- Medium severity. CVSS v3 base score is 5.0 out of 10.