CVE-2022-41952
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.
Does this matter?
Lower severity and a low EPSS score (0.87%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- EPSS
- 0.87% probability · 57th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-400, CWE-772
- Affected
- matrix/synapse
- Source
- security-advisories@github.com
References
- https://github.com/matrix-org/synapse/pull/11784Patch, Third Party Advisory
- https://github.com/matrix-org/synapse/pull/11936Patch, Third Party Advisory
- https://github.com/matrix-org/synapse/releases/tag/v1.52.0Release Notes, Third Party Advisory
- https://github.com/matrix-org/synapse/releases/tag/v1.53.0Release Notes, Third Party Advisory
- https://github.com/matrix-org/synapse/security/advisories/GHSA-4822-jvwx-w47hMitigation, Third Party Advisory
- https://github.com/matrix-org/synapse/pull/11784Patch, Third Party Advisory
- https://github.com/matrix-org/synapse/pull/11936Patch, Third Party Advisory
- https://github.com/matrix-org/synapse/releases/tag/v1.52.0Release Notes, Third Party Advisory
- https://github.com/matrix-org/synapse/releases/tag/v1.53.0Release Notes, Third Party Advisory
- https://github.com/matrix-org/synapse/security/advisories/GHSA-4822-jvwx-w47hMitigation, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.