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.
Score
A numerical rating that indicates how dangerous this vulnerability is.
9.1Critical- Published Date:Apr 8, 2026
- CISA KEV Date:*No Data*
- Industries Affected:20
Exploitability
- Score:3.9
- Attack Vector:NETWORK
- Attack Complexity:LOW
- Privileges Required:NONE
- User Interaction:NONE
- Scope:UNCHANGED
Impact
- Score:5.2
- Confidentiality Impact:HIGH
- Integrity Impact:HIGH
- Availability Impact:NONE
Description Preview
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.
Industries Affected
Below is a list of industries most commonly impacted or potentially at risk based on intelligence.