FKIE_CVE-2026-23996

Vulnerability from fkie_nvd - Published: 2026-01-21 23:15 - Updated: 2026-02-27 14:52
Severity ?
3.7 (Low) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Summary
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.
References
security-advisories@github.comhttps://github.com/Athroniaeth/fastapi-api-key/commit/310b2c5c77305f38c63c0b917539a0344071dfd8Patch
security-advisories@github.comhttps://github.com/Athroniaeth/fastapi-api-key/releases/tag/1.1.0Product, Release Notes
security-advisories@github.comhttps://github.com/Athroniaeth/fastapi-api-key/security/advisories/GHSA-95c6-p277-p87gMitigation, Patch, Vendor Advisory
Impacted products
Vendor Product Version
athroniaeth fastapi_api_key *
To clipboard 

{
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    {
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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
      "value": "FastAPI Api Key proporciona una librer\u00eda agn\u00f3stica al backend que proporciona un sistema de claves API. La versi\u00f3n 1.1.0 tiene una vulnerabilidad de canal lateral de temporizaci\u00f3n en verify_key(). El m\u00e9todo aplic\u00f3 un retraso aleatorio solo en fallos de verificaci\u00f3n, permitiendo a un atacante distinguir estad\u00edsticamente las claves API v\u00e1lidas de las inv\u00e1lidas midiendo las latencias de respuesta. Con suficientes solicitudes repetidas, un adversario podr\u00eda inferir si un key_id corresponde a una clave v\u00e1lida, acelerando potencialmente los ataques de fuerza bruta o enumeraci\u00f3n. Todos los usuarios que dependen de verify_key() para la autenticaci\u00f3n de claves API antes de la correcci\u00f3n se ven afectados. Los usuarios deben actualizar a la versi\u00f3n 1.1.0 para recibir un parche. El parche aplica un retraso aleatorio uniforme (min_delay a max_delay) a todas las respuestas independientemente del resultado, eliminando la correlaci\u00f3n de temporizaci\u00f3n. Hay disponibles algunas soluciones alternativas. A\u00f1adir un retraso fijo a nivel de aplicaci\u00f3n o fluctuaci\u00f3n aleatoria a todas las respuestas de autenticaci\u00f3n (\u00e9xito y fallo) antes de que se aplique la correcci\u00f3n y/o usar la limitaci\u00f3n de velocidad para reducir la viabilidad de los ataques de temporizaci\u00f3n estad\u00edsticos."
    }
  ],
  "id": "CVE-2026-23996",
  "lastModified": "2026-02-27T14:52:40.820",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 3.7,
          "baseSeverity": "LOW",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
          "version": "3.1"
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        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
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  "published": "2026-01-21T23:15:53.090",
  "references": [
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      "tags": [
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      "tags": [
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  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "description": [
        {
          "lang": "en",
          "value": "CWE-208"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
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}


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