> CVE-2026-53518 [HIGH]

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PUBLISHED
2026-07-15 18:16
MODIFIED
2026-07-15 18:16
CVSS_SCORE V3
7.6
EPSS (Prob. Exploit)
0.41%
Top 65.9%
DATA SOURCES:
NVD 🔗 2026-07-15 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-10-25 GITHUB 🔗 2026-10-29 OSV 🔗 2026-07-18

> 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_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_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

> MÉTRIQUES CVSS DÉTAILLÉES

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
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
Unknown (P)
Interaction inconnue
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
None (N)
Aucune interruption de service

> RÉSUMÉ DES IMPACTS

Confidentialité
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
None
Aucune interruption de service

> WEAKNESSES

CWE-362 CWE-367

> CWE DETAILED DESCRIPTIONS

CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization - The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently. | CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition - The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

> GITHUB SECURITY ADVISORY

GHSA-7w99-5wm4-3g79 HIGH

@better-auth/oauth-provider's OAuth authorization-code grant allows concurrent redemption when two token requests race the find-then-delete primitive

AFFECTED PACKAGES:
NPM / better-auth
< 1.6.11
Fixed in: 1.6.11
NPM / @better-auth/oauth-provider
>= 1.6.0, < 1.6.11
Fixed in: 1.6.11

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

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

AFFECTED PACKAGES:
Unknown / Unknown
231 versions affected
ALIASES:
GHSA-7w99-5wm4-3g79

> HISTORIQUE DES MODIFICATIONS

Première apparition
15/07/2026 18:16
Source: NVD
📊 ENRICHISSEMENT 01/11/2026 06:59
CWE
Champ modifié: Description CWE
Ancienne valeur:
CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') - The product contains a concurrent code sequence that requires temporary, exclusive access to a sh...
Nouvelle valeur:
CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization - The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but ...
📊 ENRICHISSEMENT 01/08/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') - The product contains a concurrent code sequence that requires temporary, exclusive access to a sh...
Total des modifications: 2 Dernière mise à jour: 5 days ago

> REFERENCES

https://github.com/better-auth/better-auth/commit/b4bc65a007784b2eb0efb459e5fa6f...
https://github.com/better-auth/better-auth/releases/tag/v1.6.11
https://github.com/better-auth/better-auth/security/advisories/GHSA-7w99-5wm4-3g...
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