CVE-2021-21393: fedoraproject fedora Improper Input Validation

Vulnerability summary

CVE-2021-21393 is a medium (CVSS 6.5) Improper Input Validation vulnerability in fedoraproject fedora. EPSS estimates a 1.60% chance of exploitation in the next 30 days, higher than 75.3% of scored vulnerabilities.

Timeline

1. 12-04-2021
   PublishedVulnerability first disclosed.
2. 03-08-2024
   Last modifiedVulnerability information updated.

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.

• CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.