CVE-2026-56668: ZITADEL: Unauthorized Token Privilege Escalation in OAuth2 Token Exchange

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-10 · updated 2026-07-14
Weakness: CWE-862

Description

ZITADEL is an open source identity management platform. Prior to 4.15.3, ZITADEL's OAuth2 Token Exchange endpoint for urn:ietf:params:oauth:grant-type:token-exchange does not verify that the subject token belongs to the requesting client or that requested scopes remain within the original token's scopes, allowing a low-privilege token to be exchanged for elevated permissions at another application. This issue is fixed in version 4.15.3.

Affected products

zitadel: before 4.15.3

References

https://github.com/zitadel/zitadel/commit/e2886a61670ca8fd41c9434f87036546e5620bcc
https://github.com/zitadel/zitadel/releases/tag/v4.15.3
https://github.com/zitadel/zitadel/security/advisories/GHSA-vrh8-c9cm-wh8v

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