Is CVE-2026-33979 actively exploited?

No active exploitation of CVE-2026-33979 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-33979 be exploited remotely?

Yes. CVE-2026-33979 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-33979?

CVE-2026-33979 has a CVSS score of 8.2 (HIGH).

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HIGH

CVE-2026-33979

CWE-79Published: March 27, 2026· Updated: Mar 31, 2026

8.2

CVSS v3.1

EPSS:0.01%probability of exploitation in 30 daysPercentile:1.0th

Official 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.

NVD Source

Technical Analysis

CVE-2026-33979 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in full integrity compromise (data manipulation), with a CVSS base score of 8.2.

From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.