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CVE-2021-21393 Detail

Current 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.


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  6.5 MEDIUM
Vector:  CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
Base Score:  5.3 MEDIUM
Vector:  CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: It is possible that the NVD CVSS may not match that of the CNA. The most common reason for this is that publicly available information does not provide sufficient detail or that information simply was not available at the time the CVSS vector string was assigned.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/matrix-org/synapse/pull/9321 Patch  Third Party Advisory 
https://github.com/matrix-org/synapse/pull/9393 Patch  Third Party Advisory 
https://github.com/matrix-org/synapse/security/advisories/GHSA-jrh7-mhhx-6h88 Patch  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ Mailing List  Third Party Advisory 
https://pypi.org/project/matrix-synapse/ Product  Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-20 Improper Input Validation cwe source acceptance level NIST   Contributor acceptance level GitHub, Inc.  

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Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-21393
NVD Published Date:
04/12/2021
NVD Last Modified:
11/23/2021
Source:
GitHub, Inc.