CVE-2026-53517
Race condition in refresh-token flow allows minting of multiple valid refresh tokens.
Is CVE-2026-53517 being exploited?
Not confirmed. CVE-2026-53517 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.42% probability of exploitation in the next 30 days.
How severe is CVE-2026-53517?
CVE-2026-53517 is rated High with a CVSS score of 8.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-53517?
Yes. A fix has been recorded for CVE-2026-53517. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-53517 affect?
CVE-2026-53517 affects @better-auth/oauth-provider >=1.4.8-beta.7 and <1.6.11, embedded better-auth plugin <1.6.0, TypeScript/Node.js apps using Better Auth. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-53517?
Upgrade to 1.6.11, rotate/revoke refresh tokens, enforce atomic revoke+mint
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Concurrent refresh_token exchanges bypass revocation, create forked refresh-token families enabling token replay, session persistence, and potential account takeover.
Patch when possible
- affected>= 1.4.8-beta.7 and < 1.6.0
- affected>= 1.6.0 and < 1.6.11
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.