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Werkzeug CVE-2022-29361

CRITICAL
HTTP Request/Response Smuggling (CWE-444)
2022-05-25 cve@mitre.org
9.8
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V4 - API and Web Service HTTP request consistency
Impact

CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

A remote attacker could manipulate HTTP request interpretation between frontend and backend servers by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 7.7% exploitation probability (EPSS)

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AnalysisAI

Improper parsing of HTTP requests in Pallets Werkzeug v2.1.0 and below allows attackers to perform HTTP Request Smuggling using a crafted HTTP request with multiple requests included inside the body. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This HTTP Request/Response Smuggling vulnerability could allow attackers to manipulate HTTP request interpretation between frontend and backend servers.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Enforce strict HTTP parsing, normalize requests at proxy layer, use HTTP/2 end-to-end, reject ambiguous headers.

Affected Packages

pypi werkzeug fix: 2.1.1

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in pypi

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as HTTP Request/Response Smuggling (CWE-444), which allows attackers to manipulate HTTP request interpretation between frontend and backend servers. Improper parsing of HTTP requests in Pallets Werkzeug v2.1.0 and below allows attackers to perform HTTP Request Smuggling using a crafted HTTP request with multiple requests included inside the body. NOTE: the vendor's position is that this behavior can only occur in unsupported configurations involving development mode and an HTTP server from outside the Werkzeug project Affected products include: Palletsprojects Werkzeug.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionNVD

Improper parsing of HTTP requests in Pallets Werkzeug v2.1.0 and below allows attackers to perform HTTP Request Smuggling using a crafted HTTP request with multiple requests included inside the body. NOTE: the vendor's position is that this behavior can only occur in unsupported configurations involving development mode and an HTTP server from outside the Werkzeug project

Threat Intelligence Overview

EPSS Score
7.7%
Top 6% exploitable
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 7.7%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

57
Low Medium High Critical
KEV: 0
EPSS: +8
CVSS: +49
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

HTTP request smuggling exploits inconsistencies in how front-end and back-end servers parse HTTP message boundaries.

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)NVD

cpe:2.3:a:palletsprojects:werkzeug:*:*:*:*:*:*:*:*
CVE-2024-34069 HIGH POC
7.5 May 06

Werkzeug is a comprehensive WSGI web application library. Rated high severity (CVSS 7.5), this vulnerability is remotely

CVE-2019-14322 HIGH POC
7.5 Jul 28

In Pallets Werkzeug before 0.15.5, SharedDataMiddleware mishandles drive names (such as C:) in Windows pathnames. Rated

CVE-2020-28724 MEDIUM POC
6.1 Nov 18

Open redirect vulnerability in werkzeug before 0.11.6 via a double slash in the URL. Rated medium severity (CVSS 6.1), t

CVE-2023-46136 HIGH
8.0 Oct 25

Werkzeug is a comprehensive WSGI web application library. Rated high severity (CVSS 8.0), this vulnerability is low atta

CVE-2023-25577 HIGH
7.5 Feb 14

Werkzeug is a comprehensive WSGI web application library. Rated high severity (CVSS 7.5), this vulnerability is remotely

CVE-2019-14806 HIGH
7.5 Aug 09

Pallets Werkzeug before 0.15.3, when used with Docker, has insufficient debugger PIN randomness because Docker container

CVE-2026-102598 MEDIUM POC
6.3 Sep 29

A user-controlled request path that ends in a Windows reserved device name followed by an empty NTFS alternate data stre

CVE-2025-66221 MEDIUM
6.3 Nov 29

Werkzeug is a comprehensive WSGI web application library. Rated medium severity (CVSS 6.3), this vulnerability is remote

CVE-2024-49766 MEDIUM
6.3 Oct 25

Werkzeug is a Web Server Gateway Interface web application library. Rated medium severity (CVSS 6.3), this vulnerability

CVE-2016-10516 MEDIUM
6.1 Oct 23

Cross-site scripting (XSS) vulnerability in the render_full function in debug/tbtools.py in the debugger in Pallets Werk

CVE-2026-27199 MEDIUM
5.3 Feb 21

Werkzeug versions 3.1.5 and below on Windows fail to properly filter reserved device names in the safe_join function whe

CVE-2026-21860 MEDIUM
5.3 Jan 08

Werkzeug versions prior to 3.1.5 fail to properly validate Windows reserved device names in the safe_join function, allo

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