Is CVE-2026-27199 actively exploited?

CVE-2026-27199 has no public evidence of in-the-wild exploitation as of 2026-03-03.

What is the CVSS score for CVE-2026-27199?

CVE-2026-27199 has a CVSS score of 6.3 (MEDIUM severity). 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.

How do I patch CVE-2026-27199?

Patch guidance is available from palletsprojects security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-27199.

Which products are affected by CVE-2026-27199?

1 product: palletsprojects werkzeug.

CVE-2026-27199 - remediation guidance & executive summary

Description

Werkzeug is a comprehensive WSGI web application library. Versions 3.1.5 and below, the safe_join function allows Windows device names as filenames if preceded by other path segments. This was previously reported as GHSA-hgf8-39gv-g3f2, but the added filtering failed to account for the fact that safe_join accepts paths with multiple segments, such as example/NUL. The function send_from_directory uses safe_join to safely serve files at user-specified paths under a directory. If the application is running on Windows, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely. This issue has been fixed in version 3.1.6.

CVSS Metrics

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector: network
Complexity: low
Privileges: none
User Action: none
Confidentiality: undefined
Integrity: undefined
Availability: undefined
Weaknesses: CWE-67

Metadata

Primary Vendor: PALLETSPROJECTS
Published: 2/21/2026
Last Modified: 3/3/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

palletsprojects : werkzeug

Remediation Guidance

Executive Summary

Cite this page

CVE-2026-27199. CVEDatabase.com. Retrieved 1 May 2026. https://cvedatabase.com/cve/CVE-2026-27199

View on NIST NVD

CVE-2026-27199 vulnerability