CVE-2021-29471
CVSS V2 Medium 5
CVSS V3 Medium 5.3
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.
Overview
- CVE ID
- CVE-2021-29471
- Assigner
- security-advisories@github.com
- Vulnerability Status
- Analyzed
- Published Version
- 2021-05-11T15:15:08
- Last Modified Date
- 2022-04-05T18:06:54
Weakness Enumerations
CPE Configuration (Product)
| CPE | Vulnerable | Operator | Version Start | Version End |
|---|---|---|---|---|
| cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* | 1 | OR | 1.33.2 | |
| cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* | 1 | OR |
CVSS Version 2
- Version
- 2.0
- Vector String
- AV:N/AC:L/Au:N/C:N/I:N/A:P
- Access Vector
- NETWORK
- Access Compatibility
- LOW
- Authentication
- NONE
- Confidentiality Impact
- NONE
- Integrity Impact
- NONE
- Availability Impact
- PARTIAL
- Base Score
- 5
- Severity
- MEDIUM
- Exploitability Score
- 10
- Impact Score
- 2.9
CVSS Version 3
- Version
- 3.1
- Vector String
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Attack Vector
- NETWORK
- Attack Compatibility
- LOW
- Privileges Required
- NONE
- User Interaction
- NONE
- Scope
- UNCHANGED
- Confidentiality Impact
- NONE
- Availability Impact
- LOW
- Base Score
- 5.3
- Base Severity
- MEDIUM
- Exploitability Score
- 3.9
- Impact Score
- 1.4
References
| Reference URL | Reference Tags |
|---|---|
| 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://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c | Patch Third Party Advisory |
| https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ | Mailing List Third Party Advisory |
Sources
| Source Name | Source URL |
|---|---|
| NIST | https://nvd.nist.gov/vuln/detail/CVE-2021-29471 |
| MITRE | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-29471 |
History
| Created | Old Value | New Value | Data Type | Notes |
|---|---|---|---|---|
| 2022-05-10 06:29:47 | Added to TrackCVE | |||
| 2022-12-05 02:01:36 | 2021-05-11T15:15Z | 2021-05-11T15:15:08 | CVE Published Date | updated |
| 2022-12-05 02:01:36 | 2022-04-05T18:06:54 | CVE Modified Date | updated | |
| 2022-12-05 02:01:36 | Analyzed | Vulnerability Status | updated |