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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-27199

22
FAUCET Score

CVE-2026-27199 affects Werkzeug versions 3.1.5 and below, where a flaw in the safe_join function allows attackers to trigger an indefinite hang on Windows systems. This occurs when a specially crafted path, including a Windows device name, is passed to the send_from_directory function, leading to a denial of service. The vulnerability has a CVSS score of 5.3 (Medium), indicating a low-complexity attack that can be executed remotely without authentication, resulting in a denial of service. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
< 3.1.6CPE matchmatch criteria
cpe:2.3:a:palletsprojects:werkzeug:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

6.3MEDIUM

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
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
NONE
VS Integrity
NONE
VS Availability
LOW
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.56%
Probability of exploitation in next 30 days
EPSS Percentile
43.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0056 is in the 27th percentile among its peer group of 23,705 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
pippatch availablevia ghsa
Product: werkzeugFixed in: 3.1.6

Vendor Advisories (2)

pipGHSA-29vq-49wr-vm6xmedium

Werkzeug safe_join() allows Windows special device names

Feb 19, 2026
microsoft2026-Feb/CVE-2026-27199Moderate

Werkzeug safe_join() allows Windows special device names

Feb 10, 2026

References

github.com / pallets/werkzeug/commit/f407712fdc60a09c2b3f4fe7db557703e5d9338d
Patch
github.com / pallets/werkzeug/releases/tag/3.1.6
Release Notes
github.com / pallets/werkzeug/security/advisories/GHSA-29vq-49wr-vm6x
Vendor Advisory