Pallets Werkzeug up to 3.1.5 send_from_directory windows device name

CVSS Meta Temp Score
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CTI Interest Score
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5.2$0-$5k0.00

Summaryinfo

A vulnerability identified as problematic has been detected in Pallets Werkzeug up to 3.1.5. Affected by this issue is the function send_from_directory. This manipulation causes windows device name. This vulnerability appears as CVE-2026-27199. The attack may be initiated remotely. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic was found in Pallets Werkzeug up to 3.1.5. Affected by this vulnerability is the function send_from_directory. The manipulation with an unknown input leads to a windows device name vulnerability. The CWE definition for the vulnerability is CWE-67. The product constructs pathnames from user input, but it does not handle or incorrectly handles a pathname containing a Windows device name such as AUX or CON. This typically leads to denial of service or an information exposure when the application attempts to process the pathname as a regular file. As an impact it is known to affect availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-27199 since 02/18/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

Upgrading to version 3.1.6 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch f407712fdc60a09c2b3f4fe7db557703e5d9338d is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.2

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.3
NVD Vector: 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Windows device name
CWE: CWE-67
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Werkzeug 3.1.6
Patch: f407712fdc60a09c2b3f4fe7db557703e5d9338d

Timelineinfo

02/18/2026 CVE reserved
02/21/2026 +3 days Advisory disclosed
02/21/2026 +0 days VulDB entry created
03/03/2026 +10 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-29vq-49wr-vm6x
Status: Confirmed

CVE: CVE-2026-27199 (🔒)
GCVE (CVE): GCVE-0-2026-27199
GCVE (VulDB): GCVE-100-347293

Entryinfo

Created: 02/21/2026 09:24
Updated: 03/03/2026 19:40
Changes: 02/21/2026 09:24 (70), 03/03/2026 19:40 (11)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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