CVE-2021-21274
Published Feb 26, 2021
Last updated a year ago
Overview
- 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.
- Source
- security-advisories@github.com
- NVD status
- Modified
Social media
- Hype score
- Not currently trending
Risk scores
CVSS 3.1
- Type
- Primary
- Base score
- 6.5
- Impact score
- 3.6
- Exploitability score
- 2.8
- Vector string
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- Severity
- MEDIUM
CVSS 2.0
- Type
- Primary
- Base score
- 4.3
- Impact score
- 2.9
- Exploitability score
- 8.6
- Vector string
- AV:N/AC:M/Au:N/C:N/I:N/A:P
Configurations
[
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "6C16EE11-380E-400F-9A55-6068AAF132D8",
"versionEndExcluding": "1.25.0",
"versionStartIncluding": "0.99.0"
}
],
"operator": "OR"
}
]
},
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "A930E247-0B43-43CB-98FF-6CE7B8189835"
}
],
"operator": "OR"
}
]
}
]