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.
History

Tue, 31 Mar 2026 18:30:00 +0000

Type Values Removed Values Added
First Time appeared Express Xss Sanitizer Project
Express Xss Sanitizer Project express Xss Sanitizer
CPEs cpe:2.3:a:express_xss_sanitizer_project:express_xss_sanitizer:*:*:*:*:*:node.js:*:*
Vendors & Products Express Xss Sanitizer Project
Express Xss Sanitizer Project express Xss Sanitizer

Tue, 31 Mar 2026 15:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 30 Mar 2026 07:15:00 +0000

Type Values Removed Values Added
First Time appeared Ahmedadelfahim
Ahmedadelfahim express-xss-sanitizer
Vendors & Products Ahmedadelfahim
Ahmedadelfahim express-xss-sanitizer

Sat, 28 Mar 2026 03:15:00 +0000

Type Values Removed Values Added
Description 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.
Title Express XSS Sanitizer: allowedTags/allowedAttributes bypass leads to permissive sanitization (XSS risk)
Weaknesses CWE-183
CWE-79
References
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-03-27T21:29:19.759Z

Updated: 2026-03-31T14:29:43.694Z

Reserved: 2026-03-24T22:20:06.210Z

Link: CVE-2026-33979

cve-icon Vulnrichment

Updated: 2026-03-31T14:29:39.564Z

cve-icon NVD

Status : Analyzed

Published: 2026-03-27T22:16:22.433

Modified: 2026-03-31T18:24:58.820

Link: CVE-2026-33979

cve-icon Redhat

No data.