CVE-2026-33979
CVE-2026-33979 · Express XSS Sanitizer: allowedTags/allowedAttributes bypass leads to permissive sanitization (XSS risk)
This page contains facts from public vulnerability sources. Check the original advisory before updating.
Express XSS Sanitizer is Express 4.x and 5.x middleware which sanitizes user input data (in req.body, req.query, req.headers and req.params) to prevent Cross Site Scripting (XSS) attack. A vulnerability has been identified in versions prior to 2.0.2 where restrictive sanitization configurations are silently ignored. In version 2.0.2, the validation logic has been updated to respect explicitly provided empty configurations. Now, if allowedTags or allowedAttributes are provided (even if empty), they are passed directly to sanitize-html without being overridden.
CVSS 8.2 · High · EPSS 0.4% · Fix available
- Published
- Updated
Stack: node
Affected products and versions
express-xss-sanitizer
- Versions
- < 2.0.2: Affected
No fix published
express-xss-sanitizer npm
- Affected ranges
- SEMVER: < 2.0.2
Update to 2.0.2
Original sources
- https://github.com/AhmedAdelFahim/express-xss-sanitizer/security/advisories/GHSA-3843-rr4g-m8jq
- https://github.com/AhmedAdelFahim/express-xss-sanitizer/commit/5623009ef11dcf095c163a38dea07b9cc22ad19f
- https://github.com/AhmedAdelFahim/express-xss-sanitizer/releases/tag/v2.0.2
- https://nvd.nist.gov/vuln/detail/CVE-2026-33979