CVE-2020-26237

NameCVE-2020-26237
DescriptionHighlight.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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
ReferencesDLA-2511-1
NVD severitymedium
Debian Bugs976446

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
highlight.js (PTS)stretch8.2+ds-5vulnerable
stretch (security)8.2+ds-5+deb9u1fixed
buster9.12.0+dfsg1-4vulnerable
bullseye, sid9.18.1+dfsg1-3fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
highlight.jssourcestretch8.2+ds-5+deb9u1DLA-2511-1
highlight.jssource(unstable)9.18.1+dfsg1-3976446

Notes

https://github.com/highlightjs/highlight.js/security/advisories/GHSA-vfrc-7r7c-w9mx
https://github.com/highlightjs/highlight.js/pull/2636
https://github.com/highlightjs/highlight.js/commit/7241013ae011a585983e176ddc0489a7a52f6bb0

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