High · CVSS 8.6CVE-2026-110863

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

Answer in brief

CVE-2026-110863 records a High severity (CVSS 8.6) vulnerability in Better Auth @better-auth/sso before 1.7.3 Authentication Bypass via Personal SSO Providers. The current sources do not mark it as known exploited. The current feed maps better-auth/sso (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 14, 2026Updated Oct 14, 2026Source checked Oct 15, 2026First seen by HOL Oct 14, 2026Material review Oct 14, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.6
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps better-auth/sso (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
better-auth/ssogeneric	>=1.7.0-rc.2 <1.7.3	1.7.3

Recommended response

Check inventory. Check lockfiles and deployed manifests for better-auth/sso.
Review the reported fix. Update better-auth/sso to 1.7.3 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 14, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.