CVE-2026-56668
OAuth2 token-exchange flaw allows low-privilege tokens to gain elevated scopes.
Is CVE-2026-56668 being exploited?
Not confirmed. CVE-2026-56668 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.41% probability of exploitation in the next 30 days.
How severe is CVE-2026-56668?
CVE-2026-56668 is rated High with a CVSS score of 8.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-56668?
Yes. A fix has been recorded for CVE-2026-56668. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-56668 affect?
CVE-2026-56668 affects ZITADEL < 4.15.3, OAuth2 Token Exchange endpoint (urn:ietf:params:oauth:grant-type:token-exchange). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-56668?
Upgrade ZITADEL to 4.15.3+, revoke/reissue tokens, and audit token-exchange logs.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Token-exchange endpoint fails to verify token subject or scopes, enabling privilege escalation and unauthorized access to other clients' resources.
Immediate action required
- affected< 4.15.3
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.