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Python Library Werkzeug < 3.1.9 DoS (CVE-2026-102598)

medium Nessus Plugin ID 371389

Synopsis

A Python library installed on the remote Windows host is affected by a denial of service vulnerability.

Description

The version of the Werkzeug Python package installed on the remote Windows host is prior to 3.1.9. It is, therefore, affected by a denial of service vulnerability:

 - Werkzeug is a WSGI web application library. Prior to 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. An application that runs on Windows with NTFS and serves a user-specified path ending in a special device name such as NUL: can cause the special device to open successfully and the file read to hang indefinitely.
 (CVE-2026-102598)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to Werkzeug version 3.1.9 or later.

See Also

https://github.com/pallets/werkzeug/releases/tag/3.1.9

http://www.nessus.org/u?686127cf

Plugin Details

Severity: Medium

ID: 371389

File Name: python_werkzeug_3_1_9.nasl

Version: 1.1

Type: Local

Agent: windows

Family: Windows

Published: 10/23/2026

Updated: 10/23/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Nessus

Risk Information

CVSS Score Rationale: Score based on the vendor cvssv4 vector (availability-only impact, va:l).

VPR

Risk Factor: Low

Score: 3

Percentile: 23.62

CVSS v2

Risk Factor: Medium

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS Score Source: CVE-2026-102598

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS v4

Risk Factor: Medium

Base Score: 6.3

Vector: 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

Vulnerability Information

CPE: cpe:/a:palletsprojects:werkzeug

Patch Publication Date: 9/27/2026

Vulnerability Publication Date: 9/27/2026

Reference Information

CVE: CVE-2026-102598

CWE: CWE-67

IAVB: 2026-B-0301