Vulnerability in Matrix Synapse
CVE-2022-31052
Synapse is an open source home server implementation for the Matrix chat network. In versions prior to 1.61.1 URL previews of some web pages can exhaust the available stack space for the Synapse process due to unbounded recursion. This is sometimes recoverable and leads to an error for the request causing the problem, but in other cases the Synapse process may crash altogether. It is possible to exploit this maliciously, either by malicious users on the homeserver, or by remote users sending URLs that a local user's client may automatically request a URL preview for. Remote users are not able to exploit this directly, because the URL preview endpoint is authenticated. Deployments with `url_preview_enabled: false` set in configuration are not affected. Deployments with `url_preview_enabled: true` set in configuration **are** affected. Deployments with no configuration value set for `url_preview_enabled` are not affected, because the default is `false`. Administrators of homeservers with URL previews enabled are advised to upgrade to v1.61.1 or higher. Users unable to upgrade should set `url_preview_enabled` to false.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.017 (75.7th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 76th percentile — 75.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.016 · newest: 0.017 · change: +0.000
Affected products
- Matrix Synapse
- Matrix-Org Synapse — versions < 1.61.1
- Fedoraproject Fedora — versions 35, 36
Weakness classification (CWE)
References
- github.com/matrix-org/synapse/security/advisories/GHSA-22p3-qrh9-cx32 (Third Party Advisory)
- github.com/matrix-org/synapse/commit/fa1308061802ac7b7d20e954ba7372c5ac292333 (Patch, Third Party Advisory)
- spec.matrix.org/v1.2/client-server-api/ (Vendor Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
Frequently asked questions
- What is CVE-2022-31052?
- CVE-2022-31052 is a medium-severity vulnerability in Matrix Synapse, classified under Uncontrolled Recursion. CVSS score: 6.5/10. Published 2022-06-28.
- How severe is CVE-2022-31052?
- Medium severity. CVSS v3 base score is 6.5 out of 10.