CVE-2026-40035

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.

CVSS 4.0

9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS

0.6% chance of exploitation in the next 30 days; higher than 46% of CVEs (scores of 2026-10-25)

CWE

CWE-489

Published

2026-04-08

Modified

2026-10-08

Record from

the NVD, synced 2026-10-19

Affected

• ryandfir:unfurl

Packages (OSV)

References

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

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