CVE-2026-110864

Better Auth 1.5.0-beta.12 before 1.7.7 Authentication Bypass via OAuth Proxy

State: Published
Severity: 9.1 Critical
Published: Oct 14, 2026
Updated: Oct 15, 2026
Reserved: Oct 14, 2026

Description

Better Auth from 1.5.0-beta.12 before 1.7.7 contains an authentication bypass vulnerability in the OAuth Proxy plugin that allows unauthenticated attackers to sign in as other users by forging encrypted profiles. When the proxy shares the global secret and cookie-stored state is used, attackers can obtain encrypted state for a fake profile with a victim's verified email to take over the account via implicit linking.

Scores

CVSS	Score	Vector	Source
4.0	9.1 Critical	CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N	VulnCheck
3.1	7.4 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N	VulnCheck

Weaknesses

CWE-287 Improper Authentication

Affected Products

Product	Versions
better-authbetter-auth	1.5.0-beta.12 to before 1.7.7Affected 1.7.7Not affected

References

GitHub Security Advisory (GHSA-r4xp-prcw-77qf)vendor-advisory
VulnCheck Advisory: Better Auth 1.5.0-beta.12 before 1.7.7 Authentication Bypass via OAuth Proxythird-party-advisory

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