CVE-2021-21394

Advisory

Synapse 1.28.0 includes a fix for CVE-2021-21394: Synapse before version 1.28.0 is missing input validation of some parameters on the endpoints used to confirm third-party identifiers. The bug could be used to cause excessive use of disk space and memory, leading to resource exhaustion. Note that the groups feature is not part of the Matrix specification and the chosen maximum lengths are arbitrary.
https://github.com/matrix-org/synapse/security/advisories/GHSA-w9fg-xffh-p362

Affected package

Affected versions

Fixed versions

Vulnerability changelog

This vulnerability has no description

Resources

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21394
• https://github.com/matrix-org/synapse/pull/9321
• https://pypi.org/project/matrix-synapse/
• https://github.com/matrix-org/synapse/pull/9393
• https://github.com/matrix-org/synapse/security/advisories/GHSA-w9fg-xffh-p362
• https://lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/