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[email protected]CVE-2021-41281

HistoryNov 23, 2021 - 8:15 p.m.

CVE-2021-41281

2021-11-2320:15:11

CWE-22

[email protected]

web.nvd.nist.gov

cve-2021-41281

synapse

python 3

twisted

matrix homeservers

security vulnerability

file download

remote server

4.3 Medium

CVSS2

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

PARTIAL

Availability Impact

NONE

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

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

HIGH

Availability Impact

NONE

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

0.001 Low

EPSS

Percentile

47.0%

JSON

Synapse is a package for Matrix homeservers written in Python 3/Twisted. Prior to version 1.47.1, Synapse instances with the media repository enabled can be tricked into downloading a file from a remote server into an arbitrary directory. No authentication is required for the affected endpoint. The last 2 directories and file name of the path are chosen randomly by Synapse and cannot be controlled by an attacker, which limits the impact. Homeservers with the media repository disabled are unaffected. Homeservers with a federation whitelist are also unaffected, since Synapse will check the remote hostname, including the trailing ../s, against the whitelist. Server administrators should upgrade to 1.47.1 or later. Server administrators using a reverse proxy could, at the expense of losing media functionality, may block the certain endpoints as a workaround. Alternatively, non-containerized deployments can be adapted to use the hardened systemd config.

Affected configurations

Vulners

NVD

Node

matrix-orgsynapseRange<1.47.1

CPENameOperatorVersion
matrix:synapsematrix synapselt1.47.1

CPE	Name	Operator	Version
matrix:synapse	matrix synapse	lt	1.47.1

CNA Affected

[
  {
    "product": "synapse",
    "vendor": "matrix-org",
    "versions": [
      {
        "status": "affected",
        "version": "< 1.47.1"
      }
    ]
  }
]