CVE Intelligence
High Authentication

CVE-2026-80192 — better-auth SSO before 1.6.27 Domain Ownership Authentication Bypass

@better-auth/sso before 1.6.27 (and before 1.4.8 in the 1.4.x line and before 1.7.0-rc.5 in the 1.7 prerelease line) contains two domain-ownership flaws. When domain verification is disabled, automatic organization assignment accepts unverified provider domains, allowing an authenticated organization owner/administrator to register an SSO provider for an arbitrary domain and have users with matching email domains added to the attacker's organization with default member permissions. When domain verification is enabled, a race condition between the verify-domain and update-provider endpoints can apply completed DNS proof to a different domain; combined with implicit account linking, this can link an attacker-controlled identity provider to an existing user account. Exploitation requires the SSO plugin (and, for the org-assignment path, the organization plugin) with the relevant configuration enabled.

Published Aug 26, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: VulnCheck

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.4% (30-day exploitation probability)+4
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.36%
ahead of 29% of scored CVEs · Oct 15, 2026
Affects
Better-auth
Sso
CVSS base
8.1
High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Better-auth Sso).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes matching the vulnerability class (authentication), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Better-auth Sso ≥ 1.4.8-beta.1 and < 1.4.8≥ 1.4.9 and < 1.6.27≥ 1.7.0-beta.0 and < 1.7.0-rc.5 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.6 CVSS 4.0 High — — disclosure@vulncheck.com via NIST National Vulnerability Database
8.6 CVSS 4.0 High — — VulnCheck via CVE Program (cve.org) e CISA ADP
8.1 CVSS 3.1 High 2.8 5.2 disclosure@vulncheck.com via NIST National Vulnerability Database
8.1 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
8.1 CVSS 3.1 High — — VulnCheck via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N (score shown at the top: disclosure@vulncheck.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-287 · Improper Authentication

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.36%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.
web/proxy/WAF logsnetwork IDS/IPSauthentication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · better-auth/sso
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 8.1
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Aug 26, 2026 · VulnCheck

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 13, 2026 – Oct 13, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

4 on the record

Elsewhere on this site

Better-auth
every CVE for this vendor
Authentication
same class
CWE-287
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-110863 Better Auth @better-auth/sso before 1.7.3 Authentication Bypass via Personal SSO Providers 1d
  • CVE-2026-67328 @better-auth/sso before 1.6.21 Account Takeover via SSO Aug 1, 2026
  • CVE-2026-53513 Better Auth: Server-side request forgery via unvalidated OIDC endpoints on @better-auth/sso provider registration Jul 15, 2026
  • CVE-2026-53515 Better Auth: Privilege escalation via SSO provider registration: missing admin role check in @better-auth/sso Jul 15, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-80192 is "better-auth SSO before 1.6.27 Domain Ownership Authentication Bypass", rated High. It affects Sso (Better-auth); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.1 describes technical severity. EPSS 0.36% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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