GitHub Advisoryadvisory · PyPI
GHSA-4mp3-385r-v63f Denial of service attack due to invalid JSON
HIGH
Official page ↗
- Aliases
- CVE-2020-26890
- Ecosystem
- PyPI
- Packages
- matrix-synapse
- Severity
- High
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-20
- Reviewed
- 2020-11-24
Affected packages
• PyPI matrix-synapse: < 1.20.0 → fixed in 1.20.0
Description
Impact
A denial of service attack against Matrix clients can be exploited by sending an event including invalid JSON data to Synapse. Synapse would relay the data to clients which could crash or hang. Impact is long-lasting if the event is made part of the room state.
Patches
At a minimum #8106 and #8291 must be applied. #7372 and #8124 include additional checks.
Workarounds
There are no known workarounds.
Upgrading notes
If an invalid event is accepted by an earlier Synapse it can become part of the room state and will not be fixed by upgrading Synapse. Redacting the invalid event should avoid clients receiving the invalid event.
Related
Alias · CVE (1)
- CVE-2020-26890 Matrix Synapse before 1.20.0 erroneously permits non-standard NaN, Infinity, and -Infinity JSON values in fields of m.room.member events,… vulnerability
Weakness · CWE (1)
- CWE-20 Improper Input Validation weakness
References
- https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f web
- https://nvd.nist.gov/vuln/detail/CVE-2020-26890 advisory
- https://github.com/matrix-org/synapse package
- https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2020-237.yaml web
- https://lists.fedoraproject.org/archives/list/[email protected]/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ web
- https://lists.fedoraproject.org/archives/list/[email protected]/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ web
- https://pypi.org/project/matrix-synapse web