{"id":"CVE-2026-33979","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-33979","generatedAt":"2026-10-28T07:04:20.423Z","title":"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.","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.","published":"2026-03-27T22:16:22.000Z","lastModified":"2026-06-17T10:38:22.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":8.2,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N"},"cwe":["CWE-79","CWE-183"],"affected":["express xss sanitizer project/express xss sanitizer"],"epss":{"score":0.00389,"percentile":0.32834,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.39%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/AhmedAdelFahim/express-xss-sanitizer/commit/5623009ef11dcf095c163a38dea07b9cc22ad19f","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/AhmedAdelFahim/express-xss-sanitizer/releases/tag/v2.0.2","tags":["Product","Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/AhmedAdelFahim/express-xss-sanitizer/security/advisories/GHSA-3843-rr4g-m8jq","tags":["Exploit","Mitigation","Vendor Advisory"],"source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-33979","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}