# CVE-2026-15612: Logto OIDC nonce validation bypass in OidcConnector

Source: https://junglewise.ai/threats/cve-2026-15612-logto-oidc-nonce-validation-bypass-in-oidcconnector  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-23. Updated: 2026-07-23  
License: CC BY 4.0 with a link back

CVE-2026-15612 · Severity: info · Published 2026-07-23

Logto, an open-source identity infrastructure and authentication service, contains a security flaw in how it verifies login requests. The system fails to properly validate a security token (nonce) if it is missing from the response, which could allow an attacker to reuse old authentication tokens. This weakens the security of user sessions and could potentially lead to unauthorized account access through session replay attacks.

Technologies: [Logto](https://junglewise.ai/threats/technologies/logto). Vendors: [Logto](https://junglewise.ai/threats/vendors/logto).

## Quick answers

**Is CVE-2026-15612 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-15612 being exploited in the wild.

**How severe is CVE-2026-15612?** Informational severity, published 23 July 2026.

**Which products and versions are affected?** Logto 1.10.1 to 1.37.1.

**Is there a fix for CVE-2026-15612?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-15612 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-15612?** Check whether you run Logto 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.

## Technical details

A vulnerability exists in Logto's OIDC Connector where the system fails to enforce nonce validation if the 'nonce' claim is missing from the ID token. This occurs within the OidcConnector utility logic. By omitting the nonce claim, an attacker can bypass the security check intended to ensure that an authentication response corresponds to a specific original request. This flaw facilitates replay attacks and weakens the binding between the user's session and the authentication event. The issue affects versions 1.10.1 through 1.37.1.

## Affected products

- Logto Logto 1.10.1 to 1.37.1

## Timeline

- 2026-07-23: disclosed
- 2026-07-23: advisory

## References

- [https://github.com/logto-io/logto/blob/ea3ede35028dfd0bbb6d7b239623ce0e7f6cdff8/packages/core/src/sso/OidcConnector/utils.ts](https://github.com/logto-io/logto/blob/ea3ede35028dfd0bbb6d7b239623ce0e7f6cdff8/packages/core/src/sso/OidcConnector/utils.ts)

## Related threats

- [Logto Account API authorization bypass for third-party tokens](https://junglewise.ai/threats/cve-2026-63203-logto-is-the-modern-open-source-auth-infrastructure-for-saas-and)
- [Logto SSRF in webhook and connector endpoints](https://junglewise.ai/threats/cve-2026-56739-logto-is-the-modern-open-source-auth-infrastructure-for-saas-and)
- [Logto server-side request forgery in OIDC connector creation](https://junglewise.ai/threats/cve-2026-82263-logto-server-side-request-forgery-in-oidc-connector-creation)
- [Logto server-side request forgery in webhook test endpoint](https://junglewise.ai/threats/cve-2026-82262-logto-server-side-request-forgery-in-webhook-test-endpoint)
- [Logto account takeover via improper identifier normalization](https://junglewise.ai/threats/cve-2026-15617-logto-account-takeover-via-improper-identifier-normalization)