Is CVE-2026-27199 in the CISA KEV catalog?

No. CVE-2026-27199 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-27199?

CVE-2026-27199 has a CVSS v3 base score of 5.3 (Moderate).

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

CVE-2026-27199 has an EPSS score of 0.56% (42th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-27199?

Upgrade werkzeug to 3.1.6 or later.

CVE & CISA-KEV Catalog

CVE-2026-27199

MEDIUM

5.3

CVSS v3

NVD

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.

CWE-67

How to fix

Remediation Available

werkzeugNVD

Affected:< 3.1.6Fixed in:3.1.6CVE-2026-27199derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploit Intelligence

0.56%probability of exploitation in 30 days

42ndpercentile

Moderate risk: more likely to be exploited than 42% of all known CVEs.

References

Patch1

github.com

Vendor Advisory1

github.com

Release Notes1

github.com

Embed a live status badge for CVE-2026-27199

Markdown

[![CVE-2026-27199](https://tridentstack.com/cve/badge/CVE-2026-27199.svg)](https://tridentstack.com/cve/CVE-2026-27199)

HTML

<a href="https://tridentstack.com/cve/CVE-2026-27199"><img src="https://tridentstack.com/cve/badge/CVE-2026-27199.svg" alt="CVE-2026-27199"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-03.