CVE-2022-31052

URL previews can crash Synapse media repositories or Synapse monoliths

Description

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.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 2.30% Top 20%
Vendor Advisory fedoraproject.org Vendor Advisory fedoraproject.org Vendor Advisory matrix.org
Affected: matrix-org synapse
Published at:
Updated at:

References

Link Tags
https://github.com/matrix-org/synapse/security/advisories/GHSA-22p3-qrh9-cx32 third party advisory
https://github.com/matrix-org/synapse/commit/fa1308061802ac7b7d20e954ba7372c5ac292333 third party advisory patch
https://spec.matrix.org/v1.2/client-server-api/#get_matrixmediav3preview_url vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7EARKKJZ2W7WUITFDT4EG4NVATFYJQHF/ vendor advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGSDQ4YAITCUACAB7SXQZDJIU3IQ4CJD/ vendor advisory

Frequently Asked Questions

What is the severity of CVE-2022-31052?
CVE-2022-31052 has been scored as a medium severity vulnerability.
How to fix CVE-2022-31052?
To fix CVE-2022-31052, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2022-31052 being actively exploited in the wild?
It is possible that CVE-2022-31052 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~2% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2022-31052?
CVE-2022-31052 affects matrix-org synapse.
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