High severity8.1NVD Advisory· Published Jul 15, 2026· Updated Jul 21, 2026
CVE-2026-53518
CVE-2026-53518
Description
Better Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the @better-auth/oauth-provider POST /oauth2/token endpoint for the authorization_code grant redeems a single-use authorization code through a non-atomic find-then-delete sequence, allowing two concurrent requests to pass the read step and mint independent access tokens, refresh tokens, and ID tokens; legacy /oauth2/token and /mcp/token paths in oidc-provider and mcp plugins share the same primitive. This issue is fixed in version 1.6.11.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
@better-auth/oauth-providernpm | >= 1.6.0, < 1.6.11 | 1.6.11 |
better-authnpm | < 1.6.11 | 1.6.11 |
Affected products
4cpe:2.3:a:better-auth:better-auth\/oauth-provider:*:*:*:*:*:node.js:*:*+ 2 more
- cpe:2.3:a:better-auth:better-auth\/oauth-provider:*:*:*:*:*:node.js:*:*range: >=1.6.0,<1.6.11
- cpe:2.3:a:better-auth:better_auth:*:*:*:*:*:node.js:*:*range: >=1.6.0,<1.6.11
- (no CPE)range: 1.6.0 - 1.6.11
- Range: 1.6.0 - 1.6.11
Patches
Vulnerability mechanics
References
5- github.com/better-auth/better-auth/commit/b4bc65a007784b2eb0efb459e5fa6fd8055d3ec9nvdPatchWEB
- github.com/advisories/GHSA-7w99-5wm4-3g79ghsaADVISORY
- github.com/better-auth/better-auth/security/advisories/GHSA-7w99-5wm4-3g79nvdMitigationVendor AdvisoryWEB
- nvd.nist.gov/vuln/detail/CVE-2026-53518ghsaADVISORY
- github.com/better-auth/better-auth/releases/tag/v1.6.11nvdRelease NotesWEB
News mentions
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