Information disclosure in Matrix Synapse
CVE-2023-43796
Synapse is an open-source Matrix homeserver Prior to versions 1.95.1 and 1.96.0rc1, cached device information of remote users can be queried from Synapse. This can be used to enumerate the remote users known to a homeserver. System administrators are encouraged to upgrade to Synapse 1.95.1 or 1.96.0rc1 to receive a patch. As a workaround, the `federation_domain_whitelist` can be used to limit federation traffic with a homeserver.
Vulnerability class: Information Disclosure
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.009 (58.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 58.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000
Affected products
- Matrix Synapse
- Matrix-Org Synapse — versions < 1.95.1
- Fedoraproject Fedora — versions 38, 39
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/matrix-org/synapse/security/advisories/GHSA-mp92-3jfm-3575 (Vendor Advisory)
- github.com/matrix-org/synapse/commit/daec55e1fe120c564240c5386e77941372bf458f (Patch)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (Mailing List)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (Mailing List)
- security.gentoo.org/glsa/202401-12
Frequently asked questions
- What is CVE-2023-43796?
- CVE-2023-43796 is a medium-severity vulnerability in Matrix Synapse, classified under Information Disclosure. CVSS score: 5.3/10. Published 2023-10-31.
- How severe is CVE-2023-43796?
- Medium severity. CVSS v3 base score is 5.3 out of 10.
- Is CVE-2023-43796 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.