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.

References (2)

Core 2
Core References
Vendor Advisory vendor-advisory
GHSA Advisory GHSA-vg9h-jx4v-cwx2
https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-vg9h-jx4v-cwx2
Third Party Advisory third-party-advisory
VulnCheck Advisory: dfir-unfurl - Werkzeug Debugger Exposure via String Config Parsing
https://www.vulncheck.com/advisories/dfir-unfurl-werkzeug-debugger-exposure-via-string-config-parsing

Scores

CVSS v3 9.1
EPSS 0.0056
EPSS Percentile 41.8%
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