CVE-2020-26239 Information

Description

Scratch Addons is a WebExtension that supports both Chrome and Firefox. Scratch Addons before version 1.3.2 is vulnerable to DOM-based XSS. If the victim visited a specific website the More Links addon of the Scratch Addons extension used incorrect regular expression which caused the HTML-escaped values to be unescaped leading to XSS. Scratch Addons version 1.3.2 fixes the bug. The extension will be automatically updated by the browser. More Links addon can be disabled via the option of the extension.

CVSS Vector

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

Reference

https://github.com/ScratchAddons/ScratchAddons/releases/tag/v1.3.2 https://github.com/ScratchAddons/ScratchAddons/commit/b9a52d6532c8514254c7cc1d8e18710dbedc41ff https://github.com/ScratchAddons/ScratchAddons/security/advisories/GHSA-6qfq-px3r-xj4p https://github.com/ScratchAddons/ScratchAddons/blob/a471893df403f86c9182970678175d4772a0690c/addons/more-links/userscript.js#L15

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

REQUIRED

Confidentiality Impact

CHANGED

Integrity Impact

LOW

Availability Impact

LOW

Base Score

NONE

Base Severity

5.4