CVE-2026-53518

7.6 HIGH 0.4% exploit odds Fix listed Other Library

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-07-15 18:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-07-21 16:03 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 7.6 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-07-15 18:16 UTC
Last modified: 2026-07-21 16:03 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-362 · Race condition
Record status: Analyzed

Affected

better-auth better-auth\/oauth-provider < 1.6.11
better-auth Better Auth < 1.6.11

Attack profile CVSS 4.0 · 7.6

Attack vector: Network
Complexity: Low
Attack requirements: Present
Privileges needed: None
User interaction: Passive
Confidentiality: High
Integrity: High
Availability: None

Raw vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-53518.md and follow it. Check whether this project is affected by CVE-2026-53518. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record