CVE-2026-40035

CRITICAL

Unfurl - Werkzeug Debugger Exposure via String Config Parsing

Title source: cna
STIX 2.1

Description

Unfurl through 2025.08 contains an improper input validation vulnerability in config parsing that enables Flask debug mode by default. The debug configuration value is read as a string and passed directly to app.run(), causing any non-empty string to evaluate truthy, allowing attackers to access the Werkzeug debugger and disclose sensitive information or achieve remote code execution.

Scores

CVSS v3 9.1
EPSS 0.0012
EPSS Percentile 30.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact total

Details

CWE
CWE-489
Status published
Products (2)
obsidianforensics/unfurl < 2025.08
ryandfir/unfurl < 2025.08
Published Apr 08, 2026
Tracked Since Apr 09, 2026