CVE-2026-40035

critical

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

https://www.vulncheck.com/advisories/dfir-unfurl-werkzeug-debugger-exposure-via-string-config-parsing

https://github.com/obsidianforensics/unfurl/security/advisories/GHSA-vg9h-jx4v-cwx2

Details

Source: Mitre, NVD

Published: 2026-04-08

Updated: 2026-04-13

Risk Information

CVSS v2

Base Score: 9.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 9.1

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Severity: Critical

CVSS v4

Base Score: 9.3

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Severity: Critical

EPSS

EPSS: 0.00099