Resource Exhaustion Affecting matrix-synapse package, versions <1.33.2-1


Severity

Recommended
0.0
medium
0
10

Snyk's Security Team recommends NVD's CVSS assessment

    Threat Intelligence

    EPSS
    0.15% (53rd percentile)

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  • Snyk ID SNYK-DEBIANUNSTABLE-MATRIXSYNAPSE-1290872
  • published 12 May 2021
  • disclosed 11 May 2021

How to fix?

Upgrade Debian:unstable matrix-synapse to version 1.33.2-1 or higher.

NVD Description

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

Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.33.2 "Push rules" can specify conditions under which they will match, including event_match, which matches event content against a pattern including wildcards. Certain patterns can cause very poor performance in the matching engine, leading to a denial-of-service when processing moderate length events. The issue is patched in version 1.33.2. A potential workaround might be to prevent users from making custom push rules, by blocking such requests at a reverse-proxy.

CVSS Scores

version 3.1
Expand this section

NVD

5.3 medium
  • Attack Vector (AV)
    Network
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    None
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    None
  • Integrity (I)
    None
  • Availability (A)
    Low