Detections
Analytics

CVE-2021-21393

medium

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.

References

https://pypi.org/project/matrix-synapse/

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/

https://github.com/matrix-org/synapse/security/advisories/GHSA-jrh7-mhhx-6h88

https://github.com/matrix-org/synapse/pull/9393

https://github.com/matrix-org/synapse/pull/9321

Details

Source: Mitre, NVD

Published: 2021-04-12

Updated: 2024-11-21

Risk Information

CVSS v2

Base Score: 4.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:N/A:P

Severity: Medium

CVSS v3

Base Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Severity: Medium

CVSS v4

Base Score: 6

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Severity: Medium

EPSS

EPSS: 0.00548