Vulnerability · Published Nov 23, 2020 · Assigned by GitHub_M

CVE-2020-26239Cross-Site Scripting in Scratch browser addons

High 7.6

In plain English

A high-severity cross-site scripting in ScratchAddons from ScratchAddons. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 64% of all known vulnerabilities).

Severity (CVSS 3.1)7.6High

Exploit odds (30 days)1.0%top 36.2% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
ScratchAddons	ScratchAddons	< 1.3.2

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:H/A:N

References

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