Vulnerability · Published Nov 24, 2020 · Assigned by GitHub_M
CVE-2020-26237Prototype Pollution in highlight.js
Medium 5.8
In plain English
A medium-severity security flaw in highlight.js from highlightjs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.3% (higher than 71% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | highlight.js | 9.18.1+dfsg1-3 | DEBIAN-CVE-2020-26237 |
| Debian:13 | highlight.js | 9.18.1+dfsg1-3 | DEBIAN-CVE-2020-26237 |
| Debian:14 | highlight.js | 9.18.1+dfsg1-3 | DEBIAN-CVE-2020-26237 |
| npm | highlight.js | 9.18.2 | GHSA-vfrc-7r7c-w9mx |
| npm | highlight.js | 10.1.2 | GHSA-vfrc-7r7c-w9mx |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| highlightjs | highlight.js | < 9.18.2>= 10.0.0, < 10.1.2 |
Weakness: CWE-471 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:H/A:N
References
- https://github.com/highlightjs/highlight.js/security/advisories/GHSA-vfrc-7r7c-w9mx x_refsource_CONFIRM
- https://github.com/highlightjs/highlight.js/pull/2636 x_refsource_MISC
- https://www.npmjs.com/package/highlight.js x_refsource_MISC
- https://github.com/highlightjs/highlight.js/commit/7241013ae011a585983e176ddc0489a7a52f6bb0 x_refsource_MISC
- [debian-lts-announce] 20201230 [SECURITY] [DLA 2511-1] highlight.js security update mailing-list, x_refsource_MLIST
- https://www.oracle.com/security-alerts/cpujul2022.html x_refsource_MISC