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Medium, CVSS 5.1

svg-sanitizer Bypasses Attribute Sanitization

CVE-2025-55166GHSA-22wq-q86m-83fh

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (enshrined/svg-sanitize 0.22.0), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
5.1 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N · score source
EPSS
  • CVE-2025-55166: 0.54% estimated exploitation activity in the next 30 days; percentile 45.74 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Problem The sanitization logic at https://github.com/darylldoyle/svg-sanitizer/blob/0.21.0/src/Sanitizer.php#L454-L481 only searches for lower-case attribute names (e.g. xlink:href instead of xlink:HrEf), which allows to by-pass the isHrefSafeValue check. As a result this allows cross-site scripting or linking to external domains. Proof-of-concept provided by azizk Credits The mentioned findings and proof-of-concept example were reported to the TYPO3 Security Team by the external security researcher azizk <medazizknani@gmail.com.

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-22wq-q86m-83fh

Agent brief

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# Patch Next advisory brief: CVE-2025-55166

Advisory: svg-sanitizer Bypasses Attribute Sanitization
IDs: CVE-2025-55166, GHSA-22wq-q86m-83fh
Record: https://patchnext.com/advisories/cve-2025-55166 (revision 1, source checked 26 Oct 2026, 14:34 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.1)
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 0.22.0. A vendor fix does not mean a deployment is fixed.

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

## 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://github.com/advisories/GHSA-22wq-q86m-83fh (GitHub-reviewed advisory GHSA-22wq-q86m-83fh lists affected ranges: Packagist enshrined/svg-sanitize >=0 <0.22.0)

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