CVE-2020-26237

Published: 24 November 2020

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.

Priority

Cvss 3 Severity Score

8.7

Score breakdown

Status

Package	Release	Status
highlight.js Launchpad, Ubuntu, Debian	bionic	Needs triage
	focal	Needs triage
	groovy	Ignored (end of life)
	hirsute	Ignored (end of life)
	impish	Ignored (end of life)
	jammy	Needs triage
	kinetic	Ignored (end of life, was needs-triage)
	lunar	Ignored (end of life, was needs-triage)
	mantic	Needs triage
	trusty	Does not exist
	upstream	Needs triage
	xenial	Needs triage

Severity score breakdown

Parameter	Value
Base score	8.7
Attack vector	Network
Attack complexity	Low
Privileges required	Low
User interaction	Required
Scope	Changed
Confidentiality	None
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:H

References

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