{"cve":"CVE-2026-33979","nvd":{"published":"2026-03-27T22:16:22.433","modified":"2026-06-17T10:38:22.467","status":"Analyzed","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N","score":8.2},"cwes":["CWE-79","CWE-183"],"references":["https://github.com/AhmedAdelFahim/express-xss-sanitizer/commit/5623009ef11dcf095c163a38dea07b9cc22ad19f","https://github.com/AhmedAdelFahim/express-xss-sanitizer/releases/tag/v2.0.2","https://github.com/AhmedAdelFahim/express-xss-sanitizer/security/advisories/GHSA-3843-rr4g-m8jq"],"products":["express_xss_sanitizer_project:express_xss_sanitizer"],"source":"nvd","synced_at":"2026-10-19T22:28:18.033120106+00:00"},"epss":{"cve":"CVE-2026-33979","score":0.00389,"percentile":0.33032,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-3843-rr4g-m8jq","url":"https://osv.dev/vulnerability/GHSA-3843-rr4g-m8jq","summary":"Express XSS Sanitizer: allowedTags/allowedAttributes bypass leads to permissive sanitization (XSS risk)","modified":"2026-03-30T20:19:57.372851Z","packages":[{"ecosystem":"npm","name":"express-xss-sanitizer","purl":"pkg:npm/express-xss-sanitizer","ranges":["<2.0.2"],"fixed":["2.0.2"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}