Skip to main content

Werkzeug CVE-2023-23934

LOW
Improper Input Validation (CWE-20)
2023-02-14 security-advisories@github.com
3.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V2 - Validation and Business Logic Input validation, allowlisting
Impact

CVSS score of 3.5 (LOW). Attack characteristics: adjacent network attack vector, low complexity, no privileges required, user interaction required.

Exploit ScenarioDerived

Successful exploitation could compromise the low-severity affected system.

Monitor Track and reassess. Why: LOW severity (CVSS 0.1-3.9).
Patch available 0.5% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAI

Werkzeug is a comprehensive WSGI web application library. Rated low severity (CVSS 3.5), this vulnerability is no authentication required, low attack complexity.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affected Packages

pypi werkzeug fix: 2.2.3

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 under CWE-20. Werkzeug is a comprehensive WSGI web application library. Browsers may allow "nameless" cookies that look like =value instead of key=value. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like =__Host-test=bad for another subdomain. Werkzeug prior to 2.2.3 will parse the cookie =__Host-test=bad as __Host-test=bad`. If a Werkzeug application is running next to a vulnerable or malicious subdomain which sets such a cookie using a vulnerable browser, the Werkzeug application will see the bad cookie value but the valid cookie key. The issue is fixed in Werkzeug 2.2.3. Affected products include: Palletsprojects Werkzeug. Version information: prior to 2.2.3.

Know when Werkzeug gets its next vulnerability

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources

No credit card · 7-day full trial

Severity by source

NVD PRIMARY 3.5 LOW
AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

DescriptionNVD

Werkzeug is a comprehensive WSGI web application library. Browsers may allow "nameless" cookies that look like =value instead of key=value. A vulnerable browser may allow a compromised application on an adjacent subdomain to exploit this to set a cookie like =__Host-test=bad for another subdomain. Werkzeug prior to 2.2.3 will parse the cookie =__Host-test=bad as __Host-test=bad`. If a Werkzeug application is running next to a vulnerable or malicious subdomain which sets such a cookie using a vulnerable browser, the Werkzeug application will see the bad cookie value but the valid cookie key. The issue is fixed in Werkzeug 2.2.3.

Threat Intelligence Overview

EPSS Score
0.5%
Top 60% 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 LOW
CISA KEV No
Public POC No
EPSS 0.5%
Patch available Yes
Active threat No
Deciding rule
LOW severity (CVSS 0.1-3.9)
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
Defer
Exploitation· derived
None
System Exposure· derived
Controlled
Automatable· derived
No
Human Impact· derived
Low

Priority Score

19
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +18
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

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-2022-29361 CRITICAL
9.8 May 25

Improper parsing of HTTP requests in Pallets Werkzeug v2.1.0 and below allows attackers to perform HTTP Request Smugglin

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

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy