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GitHub_MCVE-2021-21274

HistoryFeb 26, 2021 - 6:15 p.m.

CVE-2021-21274

2021-02-2618:15:12

CWE-770

CWE-400

GitHub_M

web.nvd.nist.gov

synapse

matrix

homeserver

python

pypi

cve-2021-21274

security

denial of service

federation

voip

instant messaging

CVSS2

4.3

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:M/Au:N/C:N/I:N/A:P

CVSS3

6.5

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

AI Score

6.4

Confidence

High

EPSS

0.002

Percentile

54.7%

JSON

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.

Affected configurations

Nvd

Vulners

Node

matrixsynapseRange0.99.0–1.25.0

Node

fedoraprojectfedoraMatch34

VendorProductVersionCPE
matrixsynapse*cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*
fedoraprojectfedora34cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

Vendor	Product	Version	CPE
matrix	synapse	*	cpe:2.3:a:matrix:synapse::::::::
fedoraproject	fedora	34	cpe:2.3:o:fedoraproject:fedora:34:::::::*

CNA Affected

[
  {
    "product": "synapse",
    "vendor": "matrix-org",
    "versions": [
      {
        "status": "affected",
        "version": ">=0.99.0, < 1.25.0"
      }
    ]
  }
]