enshrined/svg-sanitize: Stored XSS via DTD Entity / HTML5 Named Character Reference Collision

Exploitation

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

CVSS

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

EPSS

• CVE-2026-107380: 0.25% estimated exploitation activity in the next 30 days; percentile 17.07 (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 A crafted SVG bypasses enshrined/svg-sanitize's href validation and delivers a javascript: URL through the sanitizer unchanged. The bypass exploits a semantic mismatch between XML entity resolution (used during sanitization) and HTML5 Named Character Reference resolution (used by the browser when the SVG is rendered inline). This is a logic bug in svg-sanitize. It does NOT depend on any PHP ext/dom bug — it works on any PHP version. Affected installations: - enshrined/svg-sanitize: 45.2M Packagist downloads, 1.3M/month, 90+ dependents - WordPress Safe SVG plugin: 1M+ active installs (inline SVG rendering via themes) - TYPO3, Drupal and 90+ other Packagist dependents Vulnerability Details Mechanism 1. Attacker defines a DTD entity whose name collides with an HTML5 Named Character Reference: In XML, 	 expands to the literal string "#" (from the DTD definition). In HTML5, 	 is a Named Character Reference that resolves to U+0009 (TAB character). 2. The SVG uses this…

Published by the source

8 Oct 2026, 19:41 UTC

Last modified by the source

8 Oct 2026, 20:00 UTC

Source last checked

26 Oct 2026, 14:53 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-9rjx-3jch-6vjf

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-9rjx-3jch-6vjf

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# Patch Next advisory brief: CVE-2026-107380

Advisory: enshrined/svg-sanitize: Stored XSS via DTD Entity / HTML5 Named Character Reference Collision
IDs: CVE-2026-107380, GHSA-9rjx-3jch-6vjf
Record: https://patchnext.com/advisories/cve-2026-107380 (revision 2, source checked 26 Oct 2026, 14:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: enshrined/svg-sanitize 1.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist enshrined/svg-sanitize: affected <= 0.22.0; fixed in 1.0.0

## Suggested inspection (read-only)
- Packagist enshrined/svg-sanitize: check the installed version with your package manager.

## 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 enshrined/svg-sanitize.
- 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-9rjx-3jch-6vjf (OSV record GHSA-9rjx-3jch-6vjf lists affected ranges: Packagist enshrined/svg-sanitize >=0 <1.0.0 (fixed))
- Verified: https://github.com/advisories/GHSA-9rjx-3jch-6vjf (GitHub-reviewed advisory GHSA-9rjx-3jch-6vjf lists affected ranges: Packagist enshrined/svg-sanitize >=0 <=0.22.0)

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