En bref
- CVE-2026-23996 est une vulnérabilité FAIBLE (CVSS 3.7) touchant fastapi-api-key, fastapi api key (athroniaeth).
- Probabilité d'exploitation dans les 30 prochains jours (EPSS) : 0.29%, plus élevée que 21.8% des vulnérabilités.
- Correctif : mettre à jour vers 1.1.0 ou plus récent.
Description
Impact
Timing side-channel vulnerability in verify_key(). The method applied a random delay only on verification failures, allowing an attacker to statistically distinguish valid from invalid API keys by measuring response latencies. With enough repeated requests, an adversary could infer whether a key_id corresponds to a valid key, potentially accelerating brute-force or enumeration attacks.
Affected: all users relying on verify_key() for API key authentication prior to the fix.
Patches
Yes. Users should upgrade to version 1.1.0 (or the version containing this fix). The patch applies a uniform random delay (min_delay to max_delay) to all responses regardless of outcome, eliminating the timing correlation.
Workarounds
- Add an application-level fixed delay or random jitter to all authentication responses (success and failure) before the fix is applied.
- Use rate limiting to reduce the feasibility of statistical timing attacks.
References
NVD description
FastAPI Api Key provides a backend-agnostic library that provides an API key system. Version 1.1.0 has a timing side-channel vulnerability in verify_key(). The method applied a random delay only on verification failures, allowing an attacker to statistically distinguish valid from invalid API keys by measuring response latencies. With enough repeated requests, an adversary could infer whether a key_id corresponds to a valid key, potentially accelerating brute-force or enumeration attacks. All users relying on verify_key() for API key authentication prior to the fix are affected. Users should upgrade to version 1.1.0 to receive a patch. The patch applies a uniform random delay (min_delay to max_delay) to all responses regardless of outcome, eliminating the timing correlation. Some workarounds are available. Add an application-level fixed delay or random jitter to all authentication responses (success and failure) before the fix is applied and/or use rate limiting to reduce the feasibility of statistical timing attacks.
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