Improper Handling of Windows Device Names in Werkzeug - CVE-2026-102598
Published: September 30, 2026
Vulnerability identifier: #VU152936
CSH Severity: Medium
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-102598
CWE-ID: CWE-67
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to the "safe_join" function allows Windows device names as filenames when they have an empty ADS marker on NTFS. A remote attacker can cause reading of the file to hang indefinitely.
Affected software
Werkzeug
How to mitigate CVE-2026-102598
Install updates from vendor's website.
Werkzeug - update to 3.1.9