CVE-2021-29471
Matrix Synapse Denial-of-Service Vulnerability in Push Rules Pattern Matching
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 1.33.2 "Push rules" can specify conditions under which they will match, including `event_match`, which matches event content against a pattern including wildcards. Certain patterns can cause very poor performance in the matching engine, leading to a denial-of-service when processing moderate length events. The issue is patched in version 1.33.2. A potential workaround might be to prevent users from making custom push rules, by blocking such requests at a reverse-proxy.
INFO
Published Date :
May 11, 2021, 3:15 p.m.
Last Modified :
Nov. 7, 2023, 3:32 a.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
1.4
Exploitability Score :
3.9
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-29471.
| URL | Resource |
|---|---|
| https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c | Patch Third Party Advisory |
| https://github.com/matrix-org/synapse/releases/tag/v1.33.2 | Release Notes Third Party Advisory |
| https://github.com/matrix-org/synapse/security/advisories/GHSA-x345-32rc-8h85 | Patch Third Party Advisory |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-29471 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-29471 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
CVE Modified by [email protected]
Nov. 07, 2023
Action Type Old Value New Value Added Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ [No types assigned] Removed Reference GitHub, Inc. https://lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ -
Modified Analysis by [email protected]
Apr. 05, 2022
Action Type Old Value New Value Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ Mailing List, Third Party Advisory Added CWE NIST CWE-331 Added CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* -
CVE Modified by [email protected]
Aug. 02, 2021
Action Type Old Value New Value Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ [No Types Assigned] -
Initial Analysis by [email protected]
May. 25, 2021
Action Type Old Value New Value Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:N/I:N/A:P) Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Changed Reference Type https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c No Types Assigned https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c Patch, Third Party Advisory Changed Reference Type https://github.com/matrix-org/synapse/releases/tag/v1.33.2 No Types Assigned https://github.com/matrix-org/synapse/releases/tag/v1.33.2 Release Notes, Third Party Advisory Changed Reference Type https://github.com/matrix-org/synapse/security/advisories/GHSA-x345-32rc-8h85 No Types Assigned https://github.com/matrix-org/synapse/security/advisories/GHSA-x345-32rc-8h85 Patch, Third Party Advisory Added CPE Configuration OR *cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* versions up to (excluding) 1.33.2
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-29471 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-29471
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.15 }} 0.02%
score
0.51705
percentile