LiquidJS's strip_html filter bypass via newline characters in HTML tags enables XSS

Exploitation

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

CVSS

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

EPSS

• CVE-2026-44644: 0.25% estimated exploitation activity in the next 30 days; percentile 16.37 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The `strip_html` filter in liquidjs is intended to remove HTML tags from a string before rendering, and is widely used as an XSS sanitizer. The implementation uses a regex whose catch-all branch (` `) does not match line terminators, so any HTML tag containing a `\n` or `\r` character passes through unmodified. An attacker who can place a newline inside a tag (e.g. ` `) bypasses sanitization entirely, since browsers treat newlines as whitespace within a tag and execute the resulting `onerror`/`onload`/etc. handler. This results in stored or reflected XSS in any application that relies on `strip_html` to neutralize untrusted HTML.

Details The vulnerable code is in `src/filters/html.ts`: ```ts // src/filters/html.ts:45-49 export function strip_html (this: FilterImpl, v: string) { const str = stringify(v) this.context.memoryLimit.use(str.length) return str.replace(/ | | | /g, '') } ``` The regex has four alternations: 1. ` ` — uses `[\s\S]`, matches across newlines. 2. ` `…

Published by the source

27 May 2026, 00:09 UTC

Last modified by the source

27 Oct 2026, 15:15 UTC

Source last checked

28 Oct 2026, 06:00 UTC

1. Revision 4 · amended · 28 Oct 2026

   Amended from osv record GHSA-2qv6-9wx5-cwv4

2. Revision 3 · amended · 27 Oct 2026

   Amended from ghsa record GHSA-2qv6-9wx5-cwv4

3. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-2qv6-9wx5-cwv4

4. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-2qv6-9wx5-cwv4

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# Patch Next advisory brief: CVE-2026-44644

Advisory: LiquidJS's strip_html filter bypass via newline characters in HTML tags enables XSS
IDs: CVE-2026-44644, GHSA-2qv6-9wx5-cwv4
Record: https://patchnext.com/advisories/cve-2026-44644 (revision 4, source checked 28 Oct 2026, 06:00 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: liquidjs 10.26.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm liquidjs: affected < 10.26.0; fixed in 10.26.0

## Suggested inspection (read-only)
- `npm ls liquidjs --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 liquidjs.
- 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-2qv6-9wx5-cwv4 (OSV record GHSA-2qv6-9wx5-cwv4 lists affected ranges: npm liquidjs >=0 <=10.25.7)
- Verified: https://github.com/advisories/GHSA-2qv6-9wx5-cwv4 (GitHub-reviewed advisory GHSA-2qv6-9wx5-cwv4 lists affected ranges: npm liquidjs >=0 <=10.25.7)
- Verified: https://github.com/advisories/GHSA-2qv6-9wx5-cwv4 (GitHub-reviewed advisory GHSA-2qv6-9wx5-cwv4 lists affected ranges: npm liquidjs >=0 <10.26.0)
- Verified: https://osv.dev/vulnerability/GHSA-2qv6-9wx5-cwv4 (OSV record GHSA-2qv6-9wx5-cwv4 lists affected ranges: npm liquidjs >=0 <10.26.0 (fixed))

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