{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "1.6.11"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1f2ff4215c4affff0b140b0c0a712c0dde35659c"
            },
            {
              "fixed": "f41514ef07cfafc5dbf463bd1500aee6575d88a7"
            }
          ],
          "repo": "https://github.com/better-auth/better-auth",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-pw9m-5jxm-xr6h"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-287",
      "CWE-306",
      "CWE-345",
      "CWE-863"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53512.json"
  },
  "details": "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.",
  "id": "CVE-2026-53512",
  "modified": "2026-07-19T03:30:52.518390682Z",
  "published": "2026-07-15T17:18:09.512Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/better-auth/better-auth/releases/tag/v1.6.11"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53512.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/better-auth/better-auth/security/advisories/GHSA-pw9m-5jxm-xr6h"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53512"
    },
    {
      "type": "FIX",
      "url": "https://github.com/better-auth/better-auth/commit/1f2ff4215c4affff0b140b0c0a712c0dde35659c"
    },
    {
      "type": "FIX",
      "url": "https://github.com/better-auth/better-auth/pull/9576"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Better Auth: OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins"
}