Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-33979— Express XSS Sanitizer: allowedTags/allowedAttributes bypass leads to permissive sanitization (XSS risk)

Quick assessment

Affected
AhmedAdelFahim express-xss-sanitizer
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Express XSS Sanitizer是AhmedAdelFahim个人开发者的用于清理用户输入数据（在 req.body、req.query、req.headers 和 req.params 中）以防止跨站脚本 (XSS) 攻击。 Express XSS Sanitizer 2.0.2之前版本存在安全漏洞，该漏洞源于限制性清理配置被静默忽略，可能导致跨站脚本攻击。

CVSS 8.2 · High EPSS 0.42% · P35

Possible ATT&CK Techniques 1 AI

T1059 · Command and Scripting Interpreter
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-33979

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Express XSS Sanitizer: allowedTags/allowedAttributes bypass leads to permissive sanitization (XSS risk)
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
宽松定义的白名单
Source: CVE Program / CVE List V5
Vulnerability Title
Express XSS Sanitizer 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Express XSS Sanitizer是AhmedAdelFahim个人开发者的用于清理用户输入数据（在 req.body、req.query、req.headers 和 req.params 中）以防止跨站脚本 (XSS) 攻击。 Express XSS Sanitizer 2.0.2之前版本存在安全漏洞，该漏洞源于限制性清理配置被静默忽略，可能导致跨站脚本攻击。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
AhmedAdelFahim express-xss-sanitizer < 2.0.2 -

II. Public POCs for CVE-2026-33979

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 9214 chars
Pro+ exclusive includes:
Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
In-depth vulnerability mechanism
Trigger conditions & impact
Full executable POC code
Exploit chain & mitigation
POC zip download
100+ AI POC generations per month

III. Intelligence Information for CVE-2026-33979

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-33979 (1)

Vendor Advisories for CVE-2026-33979 (1)

Vendor Pages for CVE-2026-33979 (1)

IV. Related Vulnerabilities

Same product: express-xss-sanitizer
Same weakness: CWE-183

V. Comments for CVE-2026-33979

No comments yet

Leave a comment