Home/CVE/Unfurl through 2025.08 contains an improper input validation vulnerability in config parsing that enables Flask debug mo
CVE

CVE-2026-40035

Unfurl through 2025.08 contains an improper input validation vulnerability in config parsing that enables Flask debug mo

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.

CRITICAL · CVSS 9.1 EPSS 0.0018
Act now
  • Public exploit or PoC is available
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-489Active Debug Code
▤

Affected Products & Versions

1
ryandfir unfurl<= 2025.08
⚠

Public Exploits & PoCs

1
pocgithub.com · GHSA-vg9h-jx4v-cwx2github.com
▣

Scoring & Timeline

9.1
CRITICAL · CVSS v3.1 · disclosure@vulncheck.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD08 Apr 2026 · 10:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
SSVC triage · cisa-vulnrichment
Exploitation
poc
Automatable
yes
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://www.vulncheck.com/advisories/dfir-unfurl-werkzeug-debugger-exposure-via-string-config-parsingThird Party Advisory
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