ReDOS vulnerabities: multiple grammars

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact: Potential ReDOS vulnerabilities (exponential and polynomial RegEx backtracking) oswasp: The Regular expression Denial of Service (ReDoS) is a Denial of Service attack, that exploits the fact that most Regular Expression implementations may reach extreme situations that cause them to work very slowly (exponentially related to input size). An attacker can then cause a program using a Regular Expression to enter these extreme situations and then hang for a very long time. If are you are using Highlight.js to highlight user-provided data you are possibly vulnerable. On the client-side (in a browser or Electron environment) risks could include lengthy freezes or crashes... On the server-side infinite freezes could occur... effectively preventing users from accessing your app or service (ie, Denial of Service). This is an issue with grammars shipped with the parser (and potentially 3rd party grammars also), not the parser itself. If you are using Highlight.js with any of the…

Published by the source

4 Dec 2020, 16:47 UTC

Last modified by the source

10 Sep 2026, 03:48 UTC

Source last checked

26 Oct 2026, 12:15 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-7wwv-vh3v-89cq

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-7wwv-vh3v-89cq

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# Patch Next advisory brief: GHSA-7wwv-vh3v-89cq

Advisory: ReDOS vulnerabities: multiple grammars
IDs: GHSA-7wwv-vh3v-89cq
Record: https://patchnext.com/advisories/ghsa-7wwv-vh3v-89cq (revision 2, source checked 26 Oct 2026, 12:15 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: highlight.js 10.4.1; @highlightjs/cdn-assets 10.4.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm highlight.js: affected >= 9.0.0, < 10.4.1; fixed in 10.4.1
- npm @highlightjs/cdn-assets: affected < 10.4.1; fixed in 10.4.1

## Suggested inspection (read-only)
- `npm ls highlight.js --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @highlightjs/cdn-assets --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on highlight.js, @highlightjs/cdn-assets.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-7wwv-vh3v-89cq (OSV record GHSA-7wwv-vh3v-89cq lists affected ranges: npm highlight.js >=9.0.0 =0 <10.4.1 (fixed))
- Verified: https://github.com/advisories/GHSA-7wwv-vh3v-89cq (GitHub-reviewed advisory GHSA-7wwv-vh3v-89cq lists affected ranges: npm highlight.js >=9.0.0 =0 <10.4.1)

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