CVE-2026-56668

EUVD-2026-42967
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
GitHub_MCNA
8.1 HIGH
NETWORK
LOW
LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
zitadelzitadel
𝑥
< 4.15.3
CNA
Common Weakness Enumeration
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