CVE-2020-26237 Information

Description

Highlight.js is a syntax highlighter written in JavaScript. Highlight.js versions before 9.18.2 and 10.1.2 are vulnerable to Prototype Pollution. A malicious HTML code block can be crafted that will result in prototype pollution of the base object’s prototype during highlighting. If you allow users to insert custom HTML code blocks into your page/app via parsing Markdown code blocks (or similar) and do not filter the language names the user can provide you may be vulnerable. The pollution should just be harmless data but this can cause problems for applications not expecting these properties to exist and can result in strange behavior or application crashes i.e. a potential DOS vector. If your website or application does not render user provided data it should be unaffected. Versions 9.18.2 and 10.1.2 and newer include fixes for this vulnerability. If you are using version 7 or 8 you are encouraged to upgrade to a newer release.

CVSS Vector

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

Reference

https://github.com/highlightjs/highlight.js/security/advisories/GHSA-vfrc-7r7c-w9mx https://www.npmjs.com/package/highlight.js https://github.com/highlightjs/highlight.js/pull/2636 https://github.com/highlightjs/highlight.js/commit/7241013ae011a585983e176ddc0489a7a52f6bb0 https://lists.debian.org/debian-lts-announce/2020/12/msg00041.html

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

REQUIRED

Confidentiality Impact

CHANGED

Integrity Impact

NONE

Availability Impact

HIGH

Base Score

NONE

Base Severity

6.8