CVE-2026-33979

HIGH

8.2

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.

CVE Details

CVSS v3.1 Score8.2

SeverityHIGH

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published3/27/2026

Last Modified3/31/2026

Sourcenvd

Honeypot Sightings0

Affected Products

express_xss_sanitizer_project:express_xss_sanitizer

Weaknesses (CWE)

CWE-79CWE-183

References

https://github.com/AhmedAdelFahim/express-xss-sanitizer/commit/5623009ef11dcf095c163a38dea07b9cc22ad19f(security-advisories@github.com)

https://github.com/AhmedAdelFahim/express-xss-sanitizer/releases/tag/v2.0.2(security-advisories@github.com)

https://github.com/AhmedAdelFahim/express-xss-sanitizer/security/advisories/GHSA-3843-rr4g-m8jq(security-advisories@github.com)

IOC Correlations

No correlations recorded

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