CVE-2023-46136

High

Published: 25/10/2023(UTC)Translated: 15/06/2026(UTC)NVD NIST

Summary

The Werkzeug library has a vulnerability that allows for a remote denial of service attack by sending specially crafted multipart data. This affects versions 3.x prior to 3.0.1 and 2.x prior to 2.3.8.

Risk Assessment

An attacker can block worker processes, preventing the handling of legitimate requests and leading to application downtime.

Recommendation

It is recommended to upgrade to version 3.0.1 or 2.3.8 to mitigate this vulnerability.

Other vulnerabilities in Werkzeug

CVE-2026-102598Medium
In Werkzeug before 3.1.9, the safe_join function used by send_from_directory can allow a NUL: special-device path because safe_join checks the Windows device name without first removing an empty NTFS ADS marker. The trigger is an application running on Windows with NTFS serving a user-specified path ending in a special device name such as NUL:.

Original NVD description (English source)

Werkzeug is a comprehensive WSGI web application library. In versions on the 3.x branch prior to 3.0.1 and on the 2.x branch prior to 2.3.8, if an upload of a file that starts with CR or LF and then is followed by megabytes of data without these characters: all of these bytes are appended chunk by chunk into internal bytearray and lookup for boundary is performed on growing buffer. This allows an attacker to cause a denial of service by sending crafted multipart data to an endpoint that will parse it. The amount of CPU time required can block worker processes from handling legitimate requests. This vulnerability has been patched in version 3.0.1 and 2.3.8.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS