CVE-2023-1712: Use of hard-coded, security-relevant constants in deepset-ai/haystack

The vulnerability stems from hard-coded security constants in environment variable definitions within configuration files (docker-compose.yml and README.md), not from specific code functions. The commit diff shows hard-coded credentials/secrets like DEFAULT_ADMIN_PASSWORD, PROD_DB_PASSWORD, COOKIE_KEYS, and JWT_SECRET being defined with insecure default values. These are configuration-level issues rather than function-level vulnerabilities. The patch addresses this by removing hard-coded values and adding security warnings, but there's no evidence of vulnerable application logic functions in the provided code diffs or descriptions.