An issue was discovered in OpenStack Keystone before 29.0.2. The Keystone federated token rescoping mechanism does not propagate the original token's expiry to the newly issued token. When a federated user rescopes a token via POST /v3/auth/tokens, the handle_scoped_token() function in the mapped authentication plugin returns response data without an expires_at value. The token provider falls back to issuing a token with a fresh default TTL. By rescoping repeatedly before each token expires, a user can maintain access indefinitely, bypassing operator-configured token lifetime policies. This is a variant of CVE-2012-3426. Only deployments using federated identity (SAML2, OpenID Connect) are affected.