CVE-2026-33979
8.2
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
Exploitability: 3.9 / Impact: 4.2
Source: security-advisories@github.com (Secondary)
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.
Affected (1)
Configuration A
| Vulnerable Software | Affected Versions |
|---|---|
| Before 2.0.2 |
Related CWEs
CWE-183
Permissive List of Allowed Inputs
The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are explicitly allowed by policy because the inputs are assumed to be safe, but the list is too permissive - that is, it allows an input that is unsafe, leading to resultant weaknesses.
CWE-79
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
References (3)
Source: security-advisories@github.com
Patch
Source: security-advisories@github.com
ProductRelease Notes
Source: security-advisories@github.com
ExploitMitigationVendor Advisory
Timeline
No history available yet.