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Fencer Intel
critical 9.9

CVE-2026-123800 json

SuperTokens Core: App-scoped API key can overwrite the parent connection URI domain's credentials and take over sibling applications

published 5h ago modified 4h ago also EUVD-2026-120149

cvss
9.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
—
no EPSS score yet
public exploits
0
none known

Summary

SuperTokens Core is an open source authentication server. From 6.0.0 until 6.0.24, 7.0.23, 8.0.7, 9.0.6, 9.1.6, 9.2.7, 9.3.5, 10.0.8, 10.1.9, 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, Multitenancy.checkPermissionsForCreateOrUpdate in src/main/java/io/supertokens/multitenancy/Multitenancy.java does not adequately authorize updates to a parent connection URI domain or the base tenant. In a licensed multi-tenant deployment with multiple applications under one non-default connection URI domain and separate api_keys, an attacker holding one application's valid API key can update the parent domain because the CUD-target branch checks the domain without requiring the source application and tenant to be public. Because api_keys is not protected, the attacker can replace the parent key and then sibling application keys, read or modify sibling users, obtain sessions as those users, establish persistence through a sibling dashboard user, and lock out the sibling application's own key. In the advisory's v2 create or update handlers, omitting the optional identifier produces a base-tenant target that skips the permission branches and enterprise-feature gate, allowing changes to firstFactors, required secondary factors, and recipe-enabled flags that affect login integrity and availability. The base-target variant still rejects coreConfig and does not establish key theft. This issue is fixed in versions 6.0.24, 7.0.23, 8.0.7, 9.0.6, 9.1.6, 9.2.7, 9.3.5, 10.0.8, 10.1.9, 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.

Patch / fix

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CVSS scores

assigned by version score vector
CNA 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • supertokens supertokens-core

Classification

Weakness
  • CWE-639 Authorization Bypass Through User-Controlled Key
  • CWE-863 Incorrect Authorization

References

Sources

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.