{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23996","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-01-19T18:49:20.658Z","datePublished":"2026-01-21T22:29:24.107Z","dateUpdated":"2026-01-22T16:49:16.733Z"},"containers":{"cna":{"title":"FastAPI Api Key has a timing side-channel in verify_key that allows statistical key validity detection","problemTypes":[{"descriptions":[{"cweId":"CWE-208","lang":"en","description":"CWE-208: Observable Timing Discrepancy","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"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"}}],"references":[{"name":"https://github.com/Athroniaeth/fastapi-api-key/security/advisories/GHSA-95c6-p277-p87g","tags":["x_refsource_CONFIRM"],"url":"https://github.com/Athroniaeth/fastapi-api-key/security/advisories/GHSA-95c6-p277-p87g"},{"name":"https://github.com/Athroniaeth/fastapi-api-key/commit/310b2c5c77305f38c63c0b917539a0344071dfd8","tags":["x_refsource_MISC"],"url":"https://github.com/Athroniaeth/fastapi-api-key/commit/310b2c5c77305f38c63c0b917539a0344071dfd8"},{"name":"https://github.com/Athroniaeth/fastapi-api-key/releases/tag/1.1.0","tags":["x_refsource_MISC"],"url":"https://github.com/Athroniaeth/fastapi-api-key/releases/tag/1.1.0"}],"affected":[{"vendor":"Athroniaeth","product":"fastapi-api-key","versions":[{"version":"< 1.1.0","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-01-21T22:29:24.107Z"},"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."}],"source":{"advisory":"GHSA-95c6-p277-p87g","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-01-22T15:09:24.050000Z","id":"CVE-2026-23996","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-01-22T16:49:16.733Z"}}]}}