{"cve":"CVE-2026-53512","nvd":{"published":"2026-07-15T18:16:47.420","modified":"2026-07-21T13:33:47.543","status":"Analyzed","description":"Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, the legacy oidcProvider and mcp plugins expose OAuth token endpoints whose refresh_token grant authenticates only possession of the bound refreshToken row and matching client_id, without verifying the confidential client's client_secret, allowing an attacker with a valid refresh_token to mint access tokens and rotated refresh tokens through /api/auth/oauth2/token or /api/auth/mcp/token. The @better-auth/oauth-provider package is not affected. This issue is fixed in version 1.6.11.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","score":9.1},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","score":9.1},"cwes":["CWE-287","CWE-306","CWE-345","CWE-863"],"references":["https://github.com/better-auth/better-auth/commit/1f2ff4215c4affff0b140b0c0a712c0dde35659c","https://github.com/better-auth/better-auth/pull/9576","https://github.com/better-auth/better-auth/releases/tag/v1.6.11","https://github.com/better-auth/better-auth/security/advisories/GHSA-pw9m-5jxm-xr6h"],"products":["better-auth:better_auth"],"source":"nvd","synced_at":"2026-10-19T22:45:36.895656543+00:00"},"epss":{"cve":"CVE-2026-53512","score":0.00275,"percentile":0.19972,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-pw9m-5jxm-xr6h","url":"https://osv.dev/vulnerability/GHSA-pw9m-5jxm-xr6h","summary":"Better Auth: OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins","modified":"2026-07-20T19:30:24.092604956Z","packages":[{"ecosystem":"npm","name":"better-auth","purl":"pkg:npm/better-auth","ranges":["<1.6.11"],"fixed":["1.6.11"]}]}],"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."]}