Timing Attack Affecting fastapi-api-key package, versions [,1.1.0)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-FASTAPIAPIKEY-15054292
- published22 Jan 2026
- disclosed21 Jan 2026
- creditUnknown
Introduced: 21 Jan 2026
NewCVE-2026-23996 (opens in a new tab)How to fix?
Upgrade fastapi-api-key to version 1.1.0 or higher.
Overview
fastapi-api-key is a fastapi-api-key provides secure, production-ready API key management for FastAPI. It offers pluggable hashing strategies (Argon2 or bcrypt), backend-agnostic persistence (currently SQLAlchemy), and an optional cache layer (aiocache). Includes a Typer CLI and a FastAPI router for CRUD management of keys.
Affected versions of this package are vulnerable to Timing Attack via the verify_key function. An attacker can determine the validity of API keys by measuring response times and performing statistical analysis of the observed timing discrepancies. This can accelerate brute-force or enumeration attacks against the authentication mechanism.
Workaround
This vulnerability can be mitigated by adding an application-level fixed delay or random jitter to all authentication responses (both success and failure) and by implementing rate limiting to reduce the feasibility of statistical timing attacks.