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Vulnerabilities

Vulnerability · CVE-2026-27199

Werkzeug is a comprehensive WSGI web application library.

Published Feb 21, 2026 · catalog updated Jun 17, 2026 · Werkzeug is a comprehensive

Check if you run it

No confirmed exploitation is on record for CVE-2026-27199. EPSS is 0.56%. Act only if a listed version of Werkzeug is a comprehensive is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Werkzeug is a comprehensive).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.56%
Remediation
Advisory link
Affected products
cpe palletsprojects/werkzeug

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe palletsprojects/werkzeugversion unspecified

How to fix CVE-2026-27199

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-27199. EPSS is 0.56%. Act only if a listed version of Werkzeug is a comprehensive is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-67. EPSS 0.56%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 21, 2026 · NIST NVD

    Detected

    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 u

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 u

Sources

  • CVE.orgVulnerability recordCVE-2026-27199

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-27199

    30-day exploitation probability 0.6%

    first.org
  • NIST NVDVulnerability recordCVE-2026-27199

    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 f

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.