CVE-2026-67335

medium

Description

better-auth versions before 1.6.2 fail to validate the OAuth state parameter against the stored nonce when using cookie-backed state storage without PKCE. Attackers can forge the state parameter and supply an attacker-controlled authorization code to create authenticated sessions bound to the attacker's external identity or persistently link attacker accounts to victim profiles.

References

https://www.vulncheck.com/advisories/better-auth-before-oauth-state-validation-bypass

https://github.com/better-auth/better-auth/security/advisories/GHSA-wxw3-q3m9-c3jr

Details

Source: Mitre, NVD

Published: 2026-08-01

Updated: 2026-08-01

Risk Information

CVSS v2

Base Score: 5.4

Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:C/A:N

Severity: Medium

CVSS v3

Base Score: 5.3

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

Severity: Medium

CVSS v4

Base Score: 6

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Severity: Medium