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XSS vulnerability with discussion titles

Critical
SychO9 published GHSA-7x4w-j98p-854x Nov 18, 2022

Package

composer flarum/core (Composer)

Affected versions

>=1.5.0, <1.6.2

Patched versions

1.6.2

Description

Flarum's page title system allowed for page titles to be converted into HTML DOM nodes when pages were rendered. The change was made after v1.5 and was not noticed.

This allowed an attacker to inject malicious HTML markup using a discussion title input, either by creating a new discussion or renaming one. The XSS attack occurs after a visitor opens the relevant discussion page.

Impact

All communities running Flarum from v1.5.0 to v1.6.1 are impacted.

Patches

The vulnerability has been fixed and published as flarum/core v1.6.2. All communities running Flarum from v1.5.0 to v1.6.1 have to upgrade as soon as possible to v1.6.2 using:

composer update --prefer-dist --no-dev -a -W

You can then confirm you run the latest version using:

composer show flarum/core

Workarounds

None.

For more information

For any questions or comments on this vulnerability please visit https://discuss.flarum.org/d/27558.

For support questions create a discussion at https://discuss.flarum.org/t/support.

A reminder that if you ever become aware of a security issue in Flarum, please report it to us privately by emailing [email protected], and we will address it promptly.

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

CVE ID

CVE-2022-41938

Weaknesses

Credits