Vulnerability · Published Nov 22, 2022 · Assigned by GitHub_M
CVE-2022-41952Uncontrolled Resource Consumption in Matrix Synapse
Medium 6.5
In plain English
A medium-severity uncontrolled resource consumption in synapse from matrix-org. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 61% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:14 | matrix-synapse | 1.53.0-1 | DEBIAN-CVE-2022-41952 |
| PyPI | matrix-synapse | 1.53.0 | GHSA-4822-jvwx-w47h |
| PyPI | matrix-synapse | 1.53.0 | PYSEC-2026-663 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| matrix-org | synapse | < 1.53.0 |
Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L