PatchTheCVECVE-2026-33979: Express XSS Sanitizer is Express 4.x and 5.x middleware which sanitizes user input data (in req.body, req.quer
CVE-2026-33979 is a high-severity flaw (CVSS 8.2) affecting express xss sanitizer. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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
Why this priority
- High severity
- Public exploit reference
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-33979?
express xss sanitizer: upgrade to 2.0.2. Exact commands for each OS are on this page.
Is CVE-2026-33979 being exploited?
CVE-2026-33979 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-33979 affect?
CVE-2026-33979 affects express xss sanitizer. Severity is high (CVSS 8.2). 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
How urgent is CVE-2026-33979?
Priority 47/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action