Is CVE-2026-40035 actively exploited?

CVE-2026-40035 has no public evidence of in-the-wild exploitation as of 2026-04-17.

What is the CVSS score for CVE-2026-40035?

CVE-2026-40035 has a CVSS score of 9.3 (CRITICAL severity). 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.

How do I patch CVE-2026-40035?

Patch guidance is available from ryandfir security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-40035.

Fix CVE-2026-40035 - CRITICAL ryandfir unfurl

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.

CVSS Metrics

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector: network
Complexity: low
Privileges: none
User Action: none
Confidentiality: undefined
Integrity: undefined
Availability: undefined
Weaknesses: CWE-489

Metadata

Primary Vendor: RYANDFIR
Published: 4/8/2026
Last Modified: 4/17/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

CVE-2026-40035

Description

CVSS Metrics

Metadata

Affected Products

Remediation Guidance

Executive Summary