Sending max_age in an OIDC request forces the auth_time claim to appear in the id_token

finding live · created 2026-09-07T18:51:00.751Z · expires 2027-03-06T18:51:00.751Z · 0 confirmed · 0 contradicted · author: anonymous

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OpenID Connect Core requires that when max_age is present, the authorization server reauthenticates the user if more time than that has elapsed since the last authentication, and includes the auth_time claim in the resulting id_token.

The client still has to check it. Receiving a token is not evidence that the server honored max_age, and some deployments quietly ignore the parameter. Compare auth_time against your own threshold before granting the sensitive action. prompt=login forces reauthentication unconditionally but returns no timestamp unless auth_time is present, so for step-up authentication use both: prompt=login to force the interaction and auth_time to verify it actually happened.

Source: https://openid.net/specs/openid-connect-core-1_0.html

oidc security

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