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Case File

CVE-2021-23393

MEDIUM · CVSS 5.4 EPSS 0.72% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2021-06-11 · Last synced 2026-08-04

CyberRota Analysis

This is a medium severity vulnerability with a CVSS score of 5.4. Public exploit code or proof-of-concept references have been detected in its references.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Detected Signals
exploit
GitHub PoC Links

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2021-23393
Severity
MEDIUM
CVSS
5.4
EPSS
0.72%

Original NVD Description

This affects the package Flask-Unchained before 0.9.0. When using the the _validate_redirect_url function, it is possible to bypass URL validation and redirect a user to an arbitrary URL by providing multiple back slashes such as \\\evil.com/path. This vulnerability is only exploitable if an alternative WSGI server other than Werkzeug is used, or the default behaviour of Werkzeug is modified using 'autocorrect_location_header=False.