CVE-2021-21393: Input Validation
First published: Mon Apr 12 2021(Updated: )
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.
Credit: security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Matrix Synapse | >0.24.0<1.28.0 | |
| Fedoraproject Fedora | =34 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
- https://github.com/matrix-org/synapse/pull/9321
- https://github.com/matrix-org/synapse/pull/9393
- https://github.com/matrix-org/synapse/security/advisories/GHSA-jrh7-mhhx-6h88
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/
- https://pypi.org/project/matrix-synapse/
Frequently Asked Questions
What is CVE-2021-21393?
CVE-2021-21393 is a vulnerability in Synapse, a Matrix reference homeserver written in Python.
What is Synapse?
Synapse is a Matrix reference homeserver written in Python.
What is Matrix?
Matrix is an ecosystem for open federated Instant Messaging and VoIP.
What is the severity of CVE-2021-21393?
CVE-2021-21393 has a severity level of medium.
How do I fix CVE-2021-21393?
To fix CVE-2021-21393, update to Synapse version 1.28.0 or later.
- collector/nvd-index
- agent/severity
- agent/references
- agent/weakness
- agent/author
- agent/tags
- agent/type
- agent/description
- agent/event
- agent/last-modified-date
- agent/remedy
- agent/softwarecombine
- agent/first-publish-date
- vendor/matrix
- canonical/matrix synapse
- vendor/fedoraproject
- canonical/fedoraproject fedora
- version/fedoraproject fedora/34