# CVE-2026-123798: SuperTokens Core XML signature wrapping in SAML verification

Source: https://junglewise.ai/threats/cve-2026-123798-supertokens-core-is-an-open-source-authentication-server-from-11  
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-2026-123798 · Severity: high · CVSS 8.1 · Published 2026-11-09

SuperTokens Core is an open-source authentication server that supports SAML login. A flaw in SAML signature validation allows an attacker to forge authentication by moving genuinely signed XML elements within a SAML response, then injecting attacker-controlled identity data. An ordinary user of any configured identity provider can exploit this to impersonate other users without valid credentials.

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

## Quick answers

**Is CVE-2026-123798 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-123798 being exploited in the wild.

**How severe is CVE-2026-123798?** High severity, with a CVSS score of 8.1, published 9 November 2026.

**Which products and versions are affected?** Supertokens Core 11.3.0 to 11.3.6, 11.4.0 to 11.4.6, 12.0.0 to 12.0.9.

**Is there a fix for CVE-2026-123798?** Yes: fixed in 11.3.7, 11.4.7, 12.0.10. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-123798 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-123798?** 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 11.3.7, 11.4.7, 12.0.10

## Technical details

The vulnerability is an XML Signature Wrapping attack in the SAML.verifySamlResponseSignature method. The code validates SAML responses using OpenSAML's SignatureValidator without first applying SAMLSignatureProfileValidator, allowing a signature to be rebound to a different XML element. Both response-level and assertion-level signing are affected, and the vulnerability is reachable through SP-initiated login even with allowIDPInitiatedLogin disabled.

## Affected products

- SuperTokens Core 11.3.0 to 11.3.6, 11.4.0 to 11.4.6, 12.0.0 to 12.0.9

## Timeline

- 2026-11-09: disclosed

## References

- [https://github.com/supertokens/supertokens-core/commit/8d06b0cfb5409c5bf505051ddfcb94d66367caae](https://github.com/supertokens/supertokens-core/commit/8d06b0cfb5409c5bf505051ddfcb94d66367caae)
- [https://github.com/supertokens/supertokens-core/commit/9cba541ae2ed87b878d11b257bc9b8b78341f50a](https://github.com/supertokens/supertokens-core/commit/9cba541ae2ed87b878d11b257bc9b8b78341f50a)

## Related threats

- [SuperTokens Core session race condition in account unlink](https://junglewise.ai/threats/cve-2026-123804-supertokens-core-is-an-open-source-authentication-server-from-7)
- [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)