# CVE-2026-123804: SuperTokens Core session race condition in account unlink

Source: https://junglewise.ai/threats/cve-2026-123804-supertokens-core-is-an-open-source-authentication-server-from-7  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-09. Updated: 2026-11-09  
License: CC BY 4.0 with a link back

CVE-2026-123804 · Severity: medium · CVSS 6.8 · Published 2026-11-09

SuperTokens Core is an open source authentication server used to manage user logins and sessions. A race condition allows an attacker who controls a linked login method to retain a valid, refreshable session even after that method is unlinked from the account, potentially gaining persistent unauthorized access until the session expires. This could enable account takeover or unauthorized access to protected resources.

Technologies: [Supertokens Core](https://junglewise.ai/threats/technologies/supertokens-core). Vendors: [Supertokens](https://junglewise.ai/threats/vendors/supertokens).

## Quick answers

**Is CVE-2026-123804 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-123804 being exploited in the wild.

**How severe is CVE-2026-123804?** Medium severity, with a CVSS score of 6.8, published 9 November 2026.

**Which products and versions are affected?** Supertokens Core 7.0.0 until 11.0.9, 11.1.4, 11.2.4, 11.3.8, 11.4.8, 12.0.11, 12.1.2, 12.2.1, and 12.3.1.

**Is there a fix for CVE-2026-123804?** Yes: fixed in 11.0.9, 11.1.4, 11.2.4, 11.3.8, 11.4.8, 12.0.11, 12.1.2, 12.2.1, and 12.3.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-123804 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-123804?** Check whether you run Supertokens Core at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 11.0.9, 11.1.4, 11.2.4, 11.3.8, 11.4.8, 12.0.11, 12.1.2, 12.2.1, and 12.3.1

## Technical details

A race condition exists between session creation (createNewSession) and account unlinking (unlinkAccounts) where a session can be inserted after the primary user is resolved but before the unlink process revokes existing sessions. An attacker controlling a linked login method can exploit this timing window to maintain a valid, database-backed, refreshable session under the former primary identity. The vulnerability is a logic error in transaction serialization affecting versions 7.0.0 through 12.3.1.

## Affected products

- SuperTokens Core 7.0.0 until 11.0.9, 11.1.4, 11.2.4, 11.3.8, 11.4.8, 12.0.11, 12.1.2, 12.2.1, and 12.3.1

## Timeline

- 2026-11-09: disclosed

## References

- [https://github.com/supertokens/supertokens-core/commit/182b39454ac44649cdef22d87f296a38a0b1a602](https://github.com/supertokens/supertokens-core/commit/182b39454ac44649cdef22d87f296a38a0b1a602)
- [https://github.com/supertokens/supertokens-core/commit/378e1157dc26232a518d2c360ee60cf93c2fd8a2](https://github.com/supertokens/supertokens-core/commit/378e1157dc26232a518d2c360ee60cf93c2fd8a2)

## Related threats

- [SuperTokens Core cross-tenant WebAuthn authentication bypass](https://junglewise.ai/threats/cve-2026-123803-supertokens-core-is-an-open-source-authentication-server-from-10)
- [SuperTokens Core SAML authentication bypass](https://junglewise.ai/threats/cve-2026-123802-supertokens-core-is-an-open-source-authentication-server-from-11)
- [SuperTokens Core SAML replay protection bypass in callback](https://junglewise.ai/threats/cve-2026-123801-supertokens-core-is-an-open-source-authentication-server-from-11)
- [SuperTokens Core authorization bypass in multitenancy connection URI updates](https://junglewise.ai/threats/cve-2026-123800-supertokens-core-is-an-open-source-authentication-server-from-6)
- [SuperTokens Core dashboard session expiry enforcement](https://junglewise.ai/threats/cve-2026-123799-supertokens-core-is-an-open-source-authentication-server-from-11)