CVEvulnerability

CVE-2021-21394

6.5 MEDIUM Published 2021-04-12 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2021-04-12
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
5.3 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1 ([email protected])
6.5 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0 ([email protected])
4.0 MEDIUM — AV:N/AC:L/Au:S/C:N/I:N/A:P
Weaknesses
CWE-20

Description

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 1.28.0 Synapse is missing input validation of some parameters on the endpoints used to confirm third-party identifiers could 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. Not all clients might abide by them. Refer to referenced GitHub security advisory for additional details including workarounds.

Affected configurations

• matrix synapse (> 0.17.0 < 1.28.0) • fedoraproject fedora 34

Related

Weakness · CWE (1)

  • CWE-20 Improper Input Validation weakness

References