Cross-site Scripting (XSS) Affecting matrix-synapse package, versions <1.21.1-1


Severity

Recommended
0.0
medium
0
10

Snyk's Security Team recommends NVD's CVSS assessment

    Threat Intelligence

    EPSS
    0.23% (62nd percentile)

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  • Snyk ID SNYK-DEBIANUNSTABLE-MATRIXSYNAPSE-1019436
  • published 20 Oct 2020
  • disclosed 19 Oct 2020

How to fix?

Upgrade Debian:unstable matrix-synapse to version 1.21.1-1 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.

AuthRestServlet in Matrix Synapse before 1.21.0 is vulnerable to XSS due to unsafe interpolation of the session GET parameter. This allows a remote attacker to execute an XSS attack on the domain Synapse is hosted on, by supplying the victim user with a malicious URL to the /_matrix/client/r0/auth//fallback/web or /_matrix/client/unstable/auth//fallback/web Synapse endpoints.

CVSS Scores

version 3.1
Expand this section

NVD

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