CVE-2025-47278
Flask uses fallback key instead of current signing key
Executive Summary
CVE-2025-47278 is a high severity vulnerability affecting pii-secrets. It is classified as an undisclosed flaw. Ensure your systems and dependencies are patched immediately to mitigate exposure risks.
Precogs AI Insight
"Precogs PII & Secrets Scanner automatically identifies hardcoded credentials, exposed API keys, and personally identifiable information leaks across repositories, CI/CD pipelines, and deployed artifacts."
What is this vulnerability?
CVE-2025-47278 is categorized as a critical Sensitive Data Exposure flaw. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.
In Flask 3.1.0, the way fallback key configuration was handled resulted in the last fallback key being used for signing, rather than the current signing ke.
This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.
Risk Assessment
| Metric | Value |
|---|---|
| CVSS Base Score | 7.5 (HIGH) |
| Vector String | N/A |
| Published | May 13, 2025 |
| Last Modified | February 4, 2026 |
| Related CWEs | N/A |
Impact on Systems
✅ Authentication Bypass: Leaked credentials allow attackers to impersonate legitimate users or systems.
✅ Data Breach: Exposed PII triggers regulatory violations (GDPR/CCPA) and massive reputational damage.
✅ Lateral Movement: Exposed API tokens can be used to pivot deeper into internal infrastructure.
How to fix this issue?
Implement the following strategic mitigations immediately to eliminate the attack surface.
1. Secret Management Migrate all hardcoded secrets to a secure vault (e.g., AWS Secrets Manager, HashiCorp Vault).
2. Data Masking Implement automated redaction for logs to prevent PII/credentials from leaking into observability platforms.
3. Automated Scanning Deploy Precogs Secrets Scanner in pre-commit hooks and CI pipelines to prevent secret commits.
Vulnerability Signature
// Generic Secrets Exposure Vector
// DANGEROUS: Hardcoded secrets in source control or logs
const apiKey = "sk_live_1234567890abcdef";
console.log(`Connecting to API with key $\{apiKey\}`);
// SECURED: Secrets fetched from environment at runtime
const apiKey = process.env.API_SECRET_KEY;
if (!apiKey) throw new Error("API configuration missing");
// Never log secrets
console.log('Connecting to API... [REDACTED]');