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Fencer Intel
medium 6.8

CVE-2026-123804 json

SuperTokens Core: A session created concurrently with account unlink survives the unlink

published 26d ago modified 2d ago also EUVD-2026-120229 , GHSA-2pc4-vw9j-454c

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository supertokens/supertokens-core. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

SuperTokens Core is an open source authentication server. From 7.0.0 until 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, createNewSession can resolve a primary user before unlinkAccounts detaches a login method and then insert the session after unlink has enumerated and revoked the existing sessions. A user who controls the linked login method can exploit this race to retain a signed, database-backed, refreshable session as the former primary identity after that method is unlinked; the session persists until expiry or explicit revocation. This issue is fixed in versions 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

Is CVE-2026-123804 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected products

  • supertokens supertokens-core

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
  • CWE-613 DEPRECATED: Insufficient Session Expiration

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.

The maintainers of supertokens/supertokens-core published their own advisory on GitHub. Reviewed sources take precedence over it.