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MEDIUM

GHSA-22wq-q86m-83fh

svg-sanitizer Bypasses Attribute Sanitization

Quick fix

GHSA-22wq-q86m-83fh — enshrined/svg-sanitize: upgrade to the fixed version with the command below.

composer require enshrined/svg-sanitize:^0.22.0

Details

#### 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>`.

Are you affected?

Enter the version of the package you're using.

Affected packages

Packagist/enshrined/svg-sanitize
Introduced in: 0Fixed in: 0.22.0
Fixcomposer require enshrined/svg-sanitize:^0.22.0

References