Medium 5.3Published Aug 1, 2026

CVE-2026-67335better-auth before 1.6.2 OAuth State Validation Bypass

Updated under an hour ago (Oct 26, 2026, 7:50 PM ET)

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It affects better-auth. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
Weakness (CWE): CWE-287
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: VulnCheck
NVD analysis: Deferred
Record last updated: Aug 3, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

better-auth better-auth better_auth:better_auth (from the name)	before 1.6.2; 1.6.2 not affected	CNA record

References

References

https://github.com/better-auth/better-auth/security/advisories/GHSA-wxw3-q3m9-c3jr	vendor-advisory
https://www.vulncheck.com/advisories/better-auth-before-oauth-state-validation-bypass	third-party-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.