CVE-2021-21394 — Improper Input Validation in Synapse
Severity
6.5MEDIUMNVD
CNA5.3
EPSS
0.5%
top 33.20%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
Timeline
PublishedApr 12
Latest updateApr 13
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 arbitrar…
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitability: 2.8 | Impact: 3.6
Affected Packages2 packages
Also affects: Fedora 34
Patches
🔴Vulnerability Details
4OSV▶
Denial of service (via resource exhaustion) due to improper input validation on third-party identifier endpoints↗2021-04-13
GHSA▶
Denial of service (via resource exhaustion) due to improper input validation on third-party identifier endpoints↗2021-04-13
OSV▶
CVE-2021-21394: Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse)↗2021-04-12
CVEList▶
Denial of service (via resource exhaustion) due to improper input validation on third-party identifier endpoints↗2021-04-12
📋Vendor Advisories
1Debian▶
CVE-2021-21394: matrix-synapse - Synapse is a Matrix reference homeserver written in python (pypi package matrix-...↗2021