CVE-2026-123802
Received
Received - Intake
Authentication Bypass in SuperTokens Core via SAML Assertion
Vulnerability report for CVE-2026-123802, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-11-09
Last updated on: 2026-11-09
Assigner: GitHub, Inc.
Description
Description
SuperTokens Core is an open source authentication server. From 11.3.0 until 11.3.8, 11.4.8, 12.0.11, 12.1.2, 12.2.1, and 12.3.1, a licensed deployment with a configured SAML client can authenticate an identity from an assertion that did not satisfy the audience check. When the identity provider uses assertion-level signing, an attacker who has a still-valid IdP-signed assertion naming the victim for any audience and the attacker's own valid assertion for the target audience can combine them because validateSamlResponseAudience accepts an audience from one assertion while extractAllClaims takes the final NameID and attributes from another; response-level signing does not expose this multi-assertion variant. Independently, an assertion from an identity provider configured for the target deployment but issued to another SuperTokens deployment using the shared default saml_sp_entity_id can satisfy the target's audience check. Successful exploitation authenticates the attacker as the victim IdP user. This issue is fixed in versions 11.3.8, 11.4.8, 12.0.11, 12.1.2, 12.2.1, and 12.3.1.
CVSS Scores
EPSS Scores
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| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| supertokens | core | From 11.3.0 (inc) to 11.3.8 (inc) |
| supertokens | core | 11.4.8 |
| supertokens | core | 12.0.11 |
| supertokens | core | 12.1.2 |
| supertokens | core | 12.2.1 |
| supertokens | core | 12.3.1 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-345 | The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. |
| CWE-1220 | The product implements access controls via a policy or other feature with the intention to disable or restrict accesses (reads and/or writes) to assets in a system from untrusted agents. However, implemented access controls lack required granularity, which renders the control policy too broad because it allows accesses from unauthorized agents to the security-sensitive assets. |
| CWE-287 | When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. |
