> CVE-2026-27199 [MEDIUM]

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PUBLISHED
2026-02-21 06:17
MODIFIED
2026-02-21 06:17
CVSS_SCORE V3
6.3
EPSS (Prob. Exploit)
0.61%
Top 51.6%
DATA SOURCES:
NVD đź”— 2026-02-21 CWE MITRE đź”— 2026-11-01 FIRST EPSS đź”— 2026-10-25 GITHUB đź”— 2026-11-04 OSV đź”— 2026-07-26 MSRC đź”— 2026-11-02

> 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.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_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

> MÉTRIQUES CVSS DÉTAILLÉES

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
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
None (N)
Aucune divulgation d'informations
I (Impact Intégrité)
Integrity Impact
None (N)
Aucune modification de données possible
A (Impact Disponibilité)
Availability Impact
Low (L)
Interruption partielle du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
None
Aucune divulgation d'informations
Intégrité
None
Aucune modification de données possible
Disponibilité
Low
Interruption partielle du service possible

> WEAKNESSES

CWE-67

> CWE DETAILED DESCRIPTIONS

CWE-67: Improper Handling of Windows Device Names - 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.

> GITHUB SECURITY ADVISORY

GHSA-29vq-49wr-vm6x MODERATE

Werkzeug safe_join() allows Windows special device names

AFFECTED PACKAGES:
PIP / werkzeug
< 3.1.6
Fixed in: 3.1.6

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Werkzeug safe_join() allows Windows special device names

AFFECTED PACKAGES:
Unknown / Unknown
28 versions affected
ALIASES:
GHSA-29vq-49wr-vm6x, PYSEC-2026-2320

> HISTORIQUE DES MODIFICATIONS

Première apparition
21/02/2026 06:17
Source: NVD
📊 ENRICHISSEMENT 01/03/2026 06:46
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-67: Improper Handling of Windows Device Names - The product constructs pathnames from user input, but it does not handle or incorrectly handles a pathname containing a Windows device name such as ...
Total des modifications: 1 Dernière mise à jour: 8 months ago

> REFERENCES

https://github.com/pallets/werkzeug/commit/f407712fdc60a09c2b3f4fe7db557703e5d93...
https://github.com/pallets/werkzeug/releases/tag/3.1.6
https://github.com/pallets/werkzeug/security/advisories/GHSA-29vq-49wr-vm6x
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