PyPI/matrix-synapse CVE-2020-26257: medium 6.5, EPSS 2.39%

Denial of service attack via incorrect parameters in Matrix Synapse

Action: Upgrade matrix-synapse to 1.23.1 or later.

pip install matrix-synapse==1.23.1

Affected

Fixed versions

Sources

• osv: GHSA-hxmp-pqch-c8mm
• https://github.com/matrix-org/synapse/security/advisories/GHSA-hxmp-pqch-c8mm
• https://nvd.nist.gov/vuln/detail/CVE-2020-26257
• https://github.com/matrix-org/synapse/pull/8776
• https://github.com/matrix-org/synapse/commit/3ce2f303f15f6ac3dc352298972dc6e04d9b7a8b
• https://github.com/matrix-org/synapse/blob/develop/CHANGES.md#synapse-1231-2020-12-09
• https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2020-236.yaml
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DBTIU3ZNBFWZ56V4X7JIAD33V5H2GOMC
• https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QR4MMYZKX5N5GYGH4H5LBUUC5TLAFHI7

CVE-2020-26257 · published 2020-12-09T18:21:29Z · modified 2026-09-10T03:49:00.422107261Z · JSON