CVE-2021-21274
CVSS V2 Medium 4.3
CVSS V3 Medium 6.5
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 1.25.0, a malicious homeserver could redirect requests to their .well-known file to a large file. This can lead to a denial of service attack where homeservers will consume significantly more resources when requesting the .well-known file of a malicious homeserver. This affects any server which accepts federation requests from untrusted servers. Issue is resolved in version 1.25.0. As a workaround the `federation_domain_whitelist` setting can be used to restrict the homeservers communicated with over federation.
Overview
- CVE ID
- CVE-2021-21274
- Assigner
- security-advisories@github.com
- Vulnerability Status
- Analyzed
- Published Version
- 2021-02-26T18:15:12
- Last Modified Date
- 2022-10-24T20:49:17
Weakness Enumerations
CPE Configuration (Product)
| CPE | Vulnerable | Operator | Version Start | Version End |
|---|---|---|---|---|
| cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* | 1 | OR | 0.99.0 | 1.25.0 |
| cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* | 1 | OR |
CVSS Version 2
- Version
- 2.0
- Vector String
- AV:N/AC:M/Au:N/C:N/I:N/A:P
- Access Vector
- NETWORK
- Access Compatibility
- MEDIUM
- Authentication
- NONE
- Confidentiality Impact
- NONE
- Integrity Impact
- NONE
- Availability Impact
- PARTIAL
- Base Score
- 4.3
- Severity
- MEDIUM
- Exploitability Score
- 8.6
- Impact Score
- 2.9
CVSS Version 3
- Version
- 3.1
- Vector String
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- Attack Vector
- NETWORK
- Attack Compatibility
- LOW
- Privileges Required
- NONE
- User Interaction
- REQUIRED
- Scope
- UNCHANGED
- Confidentiality Impact
- NONE
- Availability Impact
- HIGH
- Base Score
- 6.5
- Base Severity
- MEDIUM
- Exploitability Score
- 2.8
- Impact Score
- 3.6
References
| Reference URL | Reference Tags |
|---|---|
| https://github.com/matrix-org/synapse/releases/tag/v1.25.0 | Third Party Advisory |
| https://github.com/matrix-org/synapse/commit/ff5c4da1289cb5e097902b3e55b771be342c29d6 | Patch Third Party Advisory |
| https://github.com/matrix-org/synapse/pull/8950 | Patch Third Party Advisory |
| https://github.com/matrix-org/synapse/security/advisories/GHSA-2hwx-mjrm-v3g8 | 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-2021-21274 |
| MITRE | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21274 |
History
| Created | Old Value | New Value | Data Type | Notes |
|---|---|---|---|---|
| 2022-05-10 06:45:06 | Added to TrackCVE | |||
| 2022-12-05 22:53:24 | 2021-02-26T18:15Z | 2021-02-26T18:15:12 | CVE Published Date | updated |
| 2022-12-05 22:53:24 | 2022-10-24T20:49:17 | CVE Modified Date | updated | |
| 2022-12-05 22:53:24 | Analyzed | Vulnerability Status | updated |