CVE-2021-21333

Severity CVSS v4.0:

Pending analysis

Type:

CWE-79 Cross-Site Scripting (XSS)

Publication date:

26/03/2021

Last modified:

07/11/2023

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 1.27.0, 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.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N CVSS v3.1 Severity and Metrics:

Base Score: 6.10 MEDIUM
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): Required
Scope (S): Changed
Confidentiality (C): None
Integrity (I): High
Availability (A): None

Base Score 3.x

6.10

Severity 3.x

MEDIUM

Vector 2.0

AV:N/AC:H/Au:N/C:N/I:P/A:N CVSS v2.0 Severity and Metrics:

Base Score: 2.60 LOW
Vector: AV:N/AC:H/Au:N/C:N/I:P/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Authentication (Au): None
Confidentiality (C): None
Integrity (I): Physical
Availability (A): None