CVE-2026-53515 json
Better Auth: Privilege escalation via SSO provider registration: missing admin role check in @better-auth/sso
published 5mo ago modified last mo. also EUVD-2026-44740 , GHSA-gv74-j8m3-fg5f
- cvss
- 7.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 37%
- public exploits
- 0
- none known
Summary
Better Auth is an authentication and authorization library for TypeScript. From 1.2.10 until 1.6.11, the @better-auth/sso plugin's POST /sso/register endpoint lets any organization member attach a new SSO provider to that organization because registerSSOProvider checks only for a membership row and does not require an owner or admin role, allowing attacker-controlled OIDC or SAML providers to drive /sso/callback/{providerId} organization provisioning. This issue is fixed in version 1.6.11.
Patch / fix
- npm @better-auth/sso 1.6.11
- better-auth better-auth/sso 1.6.11
- better-auth better_auth 1.6.11
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 3mo ago
Exploit prediction
0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N |
| GitHub | 3.1 | 7.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | @better-auth/sso | >=1.2.10, <1.6.11 |
1.6.11 |
Affected products
- better-auth better-auth
- @better-auth sso
Classification
References
-
github.com
/better-auth/better-auth/pull/9220
web, issue-tracking, patch
-
github.com
/better-auth/better-auth/commit/86765f1597378f5c3deed1b80ca91faac0a6bf00
web, patch
-
github.com
/better-auth/better-auth/security/advisories/GHSA-gv74-j8m3-fg5f
web, mitigation, vendor-advisory, advisory
-
github.com
/better-auth/better-auth/releases/tag/v1.6.11
web, release-notes
-
nvd.nist.gov
/vuln/detail/CVE-2026-53515
advisory
-
github.com
/better-auth/better-auth/issues/9133
web
-
github.com
/better-auth/better-auth
package
Sources
- CVE List CVE-2026-53515
- GitHub Advisory GHSA-gv74-j8m3-fg5f
- NVD CVE-2026-53515
- Maintainer advisory GHSA-gv74-j8m3-fg5f
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
The maintainers of better-auth/better-auth published their own advisory on GitHub. Reviewed sources take precedence over it.