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