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Fencer Intel
high 7.4

CVE-2026-123801 json

SuperTokens Core: SAML callback accepts a replayed RelayState + SAMLResponse, minting a fresh authorization code on each replay

published 5h ago modified 4h ago also EUVD-2026-120152

cvss
7.4
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 11.3.0 until 11.3.8, 11.4.8, 12.0.11, 12.1.2, 12.2.1, and 12.3.1, SAML.handleCallback does not consume RelayState, record assertion identifiers, or enforce Response.InResponseTo. In the SP-initiated flow, an attacker who obtains a legitimately issued, still-valid SAML response and its matching RelayState can resubmit the pair to /recipe/saml/callback before the assertion's NotOnOrAfter time; in the IdP-initiated flow, the assertion can be replayed without RelayState. The missing Response.InResponseTo check also permits an in-progress login to be completed with an assertion for a different identity and fails to enforce allowIDPInitiatedLogin=false. The callback does not validate Destination or SubjectConfirmationData Recipient and NotOnOrAfter, and each accepted callback mints a fresh, independently redeemable authorization code carrying the captured user's identity. 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.

Patch / fix

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CVSS scores

assigned by version score vector
CNA 3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

  • supertokens supertokens-core

Classification

Weakness
  • CWE-294 Authentication Bypass by Capture-replay
  • CWE-346 Origin Validation Error
  • CWE-384 Session Fixation

References

Sources

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