High 8.1Published Oct 14, 2026

CVE-2026-110863Better Auth @better-auth/sso before 1.7.3 Authentication Bypass via Personal SSO Providers

Updated under an hour ago (Oct 27, 2026, 10:10 PM ET)

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

EPSS puts the chance of exploitation in the next 30 days at 0.27%, higher than 19% of scored CVEs.

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Every CVE for better-auth sso

Exploited in the last 30 days

Better Auth @better-auth/sso from 1.7.0-rc.2 before 1.7.3 contains an authentication bypass vulnerability that allows authenticated users to sign in as other users by registering a personal SSO provider. Attackers can copy a legitimate provider's OIDC issuer or SAML entity ID and assert a victim's subject or NameID, because account lookup ignores providerId, creating sessions for victim accounts.

CVSS: 8.1 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Weakness (CWE): CWE-287
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.27% (percentile 19)
Assigned by: VulnCheck
NVD analysis: Awaiting Analysis
Record last updated: Oct 16, 2026
First seen by InfoSec Signals: Oct 14, 2026

Affected products

Affected products

better-auth sso better_auth:sso (from the name)	from 1.7.0-rc.2 before 1.7.3	CNA record

References

References

https://github.com/better-auth/better-auth/security/advisories/GHSA-mx9r-x6ww-qjw9	vendor-advisory
https://www.vulncheck.com/advisories/better-auth-better-auth-sso-before-1.7.3-authentication-bypass-via-personal-sso-providers	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.