High 7.6Published Jul 15, 2026

CVE-2026-53518Better Auth OAuth Provider: Race Condition in Authorization Code Exchange Enables Multi-Use Code Redemption

Updated under an hour ago (Oct 27, 2026, 3:30 AM ET)

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It affects better-auth and 2 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for better-auth

Exploited in the last 30 days

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.

CVSS: 7.6 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Weakness (CWE): CWE-362, CWE-367
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 15, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

better-auth better-auth better_auth:better_auth (from the name)	from 1.6.0, < 1.6.11	CNA record
better-auth better-auth/oauth-provider better-auth:better-auth/oauth-provider	from 1.6.0 before 1.6.11	NVD
better-auth better_auth better-auth:better_auth	from 1.6.0 before 1.6.11	NVD

References

References

https://github.com/better-auth/better-auth/security/advisories/GHSA-7w99-5wm4-3g79	x-refsource-confirm, mitigation, vendor-advisory
https://github.com/better-auth/better-auth/commit/b4bc65a007784b2eb0efb459e5fa6fd8055d3ec9	x-refsource-misc, patch
https://github.com/better-auth/better-auth/releases/tag/v1.6.11	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.