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[email protected]CVE-2021-21333

HistoryMar 26, 2021 - 8:15 p.m.

CVE-2021-21333

2021-03-2620:15:11

CWE-74

CWE-79

[email protected]

web.nvd.nist.gov

synapse

matrix

homeserver

html injection

notification emails

security vulnerability

cve-2021-21333

2.6 Low

CVSS2

Attack Vector

NETWORK

Attack Complexity

HIGH

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

PARTIAL

Availability Impact

NONE

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

6.1 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality Impact

NONE

Integrity Impact

HIGH

Availability Impact

NONE

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

6.5 Medium

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

44.2%

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 1.27.0, the notification emails sent for notifications for missed messages or for an expiring account are subject to HTML injection. In the case of the notification for missed messages, this could allow an attacker to insert forged content into the email. The account expiry feature is not enabled by default and the HTML injection is not controllable by an attacker. This is fixed in version 1.27.0.

Affected configurations

Vulners

NVD

Node

matrix-orgsynapseRange<1.27.0

CPENameOperatorVersion
matrix:synapsematrix synapselt1.27.0

CPE	Name	Operator	Version
matrix:synapse	matrix synapse	lt	1.27.0

CNA Affected

[
  {
    "product": "synapse",
    "vendor": "matrix-org",
    "versions": [
      {
        "status": "affected",
        "version": "< 1.27.0"
      }
    ]
  }
]