Uncontrolled Recursion Affecting synapse package, versions <1.61.1-r0


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.14% (51st percentile)

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  • Snyk IDSNYK-ALPINE321-SYNAPSE-8489412
  • published6 Dec 2024
  • disclosed28 Jun 2022

Introduced: 28 Jun 2022

CVE-2022-31052  (opens in a new tab)
CWE-674  (opens in a new tab)

How to fix?

Upgrade Alpine:3.21 synapse to version 1.61.1-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream synapse package and not the synapse package as distributed by Alpine. See How to fix? for Alpine:3.21 relevant fixed versions and status.

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.

CVSS Scores

version 3.1