{"cve":"CVE-2026-53517","nvd":{"published":"2026-07-15T18:16:48.107","modified":"2026-07-21T16:00:22.173","status":"Analyzed","description":"Better Auth is an authentication and authorization library for TypeScript. From 1.4.8-beta.7 until 1.6.11, the @better-auth/oauth-provider POST /oauth2/token endpoint on the refresh_token grant performs a non-atomic read, validate, revoke, and mint sequence on the oauthRefreshToken row, allowing concurrent requests with the same parent refresh token to pass the revoked check and create forked refresh-token families; the vulnerable range also includes embedded better-auth plugin versions before 1.6.0. This issue is fixed in version 1.6.11.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","score":8.1},"cwes":["CWE-362","CWE-367"],"references":["https://github.com/better-auth/better-auth/commit/c6918ecc9e3a75892169415d7f6c95b591b6a52d","https://github.com/better-auth/better-auth/releases/tag/v1.6.11","https://github.com/better-auth/better-auth/security/advisories/GHSA-392p-2q2v-4372"],"products":["better-auth:better-auth\\/oauth-provider","better-auth:better_auth"],"source":"nvd","synced_at":"2026-10-19T22:45:36.895656543+00:00"},"epss":{"cve":"CVE-2026-53517","score":0.00422,"percentile":0.36539,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-392p-2q2v-4372","url":"https://osv.dev/vulnerability/GHSA-392p-2q2v-4372","summary":"Better Auth: OAuth refresh-token rotation forks the token family on concurrent redemption","modified":"2026-07-20T19:30:24.031992434Z","packages":[{"ecosystem":"npm","name":"@better-auth/oauth-provider","purl":"pkg:npm/%40better-auth/oauth-provider","ranges":[">=1.6.0 <1.6.11"],"fixed":["1.6.11"]},{"ecosystem":"npm","name":"better-auth","purl":"pkg:npm/better-auth","ranges":[">=1.4.8-beta.7 <1.6.0"],"fixed":["1.6.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}