@better-auth/oauth-provider before 1.7.0-beta.4 fails to bind access-token audience to the authorization grant, allowing clients to request tokens for unrelated resources. Attackers can complete an OAuth flow and obtain access tokens whose audience targets resource servers the authorization never covered, bypassing intended authorization boundaries.
https://www.vulncheck.com/advisories/better-auth-oauth-provider-before-beta-4-authorization-bypass
https://github.com/better-auth/better-auth/security/advisories/GHSA-p2fr-6hmx-4528
Published: 2026-08-01
Updated: 2026-08-01
Base Score: 5.5
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:N
Severity: Medium
Base Score: 6.4
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Severity: Medium
Base Score: 5.3
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
Severity: Medium