What’s Vulnerable › Vulnerabilities

CVE-2026-53606: sanitize-html has an incomplete URI scheme validation that allows javascript: URIs through action, formaction, data, poster, and background attributes

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-12 · updated 2026-10-25
• Weakness: CWE-79

Description

ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. Versions of sanitize-html prior to 2.17.5 use `allowedSchemesAppliedToAttributes` (default: `['href', 'src', 'cite']`) to gate the `naughtyHref()` function that blocks dangerous URI schemes like `javascript:` and `vbscript:`. The HTML specification defines 10+ attributes that accept URIs (`action`, `formaction`, `data`, `poster`, `background`, `ping`, `xlink:href`, `dynsrc`, `lowsrc`), but none of these are included in the default gate list. When a developer allows any of these attributes in their configuration, `javascript:` URIs pass through completely unmodified, enabling XSS. Version 2.17.5 patches the issue.

Affected products

• apostrophecms sanitize-html: before 2.17.5

References

• https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-vccv-cmxp-4j9h
• https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-vccv-cmxp-4j9h

Get alerted when CVE-2026-53606 or the next vulnerability affects your stack