CVE-2022-41952

Uncontrolled Resource Consumption in Matrix Synapse

Description

Synapse before 1.52.0 with URL preview functionality enabled will attempt to generate URL previews for media stream URLs without properly limiting connection time. Connections will only be terminated after `max_spider_size` (default: 10M) bytes have been downloaded, which can in some cases lead to long-lived connections towards the streaming media server (for instance, Icecast). This can cause excessive traffic and connections toward such servers if their stream URL is, for example, posted to a large room with many Synapse instances with URL preview enabled. Version 1.52.0 implements a timeout mechanism which will terminate URL preview connections after 30 seconds. Since generating URL previews for media streams is not supported and always fails, 1.53.0 additionally implements an allow list for content types for which Synapse will even attempt to generate a URL preview. Upgrade to 1.53.0 to fully resolve the issue. As a workaround, turn off URL preview functionality by setting `url_preview_enabled: false` in the Synapse configuration file.

Categories

6.5
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.06%
Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com
Affected: matrix-org synapse
Published at:
Updated at:

References

Link Tags
https://github.com/matrix-org/synapse/security/advisories/GHSA-4822-jvwx-w47h mitigation third party advisory
https://github.com/matrix-org/synapse/pull/11784 third party advisory patch
https://github.com/matrix-org/synapse/pull/11936 third party advisory patch
https://github.com/matrix-org/synapse/releases/tag/v1.52.0 third party advisory release notes
https://github.com/matrix-org/synapse/releases/tag/v1.53.0 third party advisory release notes

Frequently Asked Questions

What is the severity of CVE-2022-41952?
CVE-2022-41952 has been scored as a medium severity vulnerability.
How to fix CVE-2022-41952?
To fix CVE-2022-41952, 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-2022-41952 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2022-41952 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2022-41952?
CVE-2022-41952 affects matrix-org synapse.
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