Deprecate decode_id_token and stop validating ID tokens (#911)#943
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MSAL should not perform any ID token validation. Per OpenID Connect, an ID token obtained via direct communication with the token endpoint (how MSAL retrieves tokens) does not need client-side validation, and MSAL does not manage sessions, so it should not check exp/iss/aud. - Add non-validating _decode_id_token_claims() and use it on the retrieval path (Client._obtain_token and TokenCache) so no iss/aud/exp/nbf checks run - Deprecate the public decode_id_token() function and Client.decode_id_token() method with a DeprecationWarning - Keep nonce and max_age/auth_time auth-code-flow replay protections - Update docstrings that claimed the SDK validates the ID token - Update tests accordingly Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Pull request overview
This PR updates MSAL’s ID token handling to stop performing ID token validation during token acquisition/caching, while deprecating the public decode_id_token() API and adjusting tests accordingly.
Changes:
- Add a non-validating internal
_decode_id_token_claims()and use it in token acquisition (Client._obtain_token) and token caching (TokenCache). - Deprecate
decode_id_token()andClient.decode_id_token()withDeprecationWarning, and update unit tests to assert the warning behavior. - Ensure retrieval paths only decode claims (no
iss/aud/exp/nbfchecks) while leaving replay protections to the auth-code-flow logic that consumesid_token_claims.
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.
| File | Description |
|---|---|
msal/oauth2cli/oidc.py |
Introduces non-validating claim decode helper; deprecates legacy ID token validation APIs; switches token acquisition to populate id_token_claims via non-validating decode. |
msal/token_cache.py |
Stops validating ID tokens when extracting claims for caching/account parsing; uses non-validating decode helper instead. |
tests/test_oidc.py |
Updates tests to expect deprecation warnings from decode_id_token() and adds coverage asserting the internal helper does not validate expired tokens. |
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…view) - Add stacklevel=2 so the DeprecationWarning points at the caller's site - Reword warning and docstrings to avoid implying this legacy helper is non-validating; clarify that only token acquisition stopped validating while decode_id_token() still performs legacy validation Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
bgavrilMS
approved these changes
Jul 15, 2026
gladjohn
approved these changes
Jul 16, 2026
Avery-Dunn
approved these changes
Jul 20, 2026
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MSAL should not perform any ID token validation. Per OpenID Connect, an ID token obtained via direct communication with the token endpoint (how MSAL retrieves tokens) does not need client-side validation, and MSAL does not manage sessions, so it should not check exp/iss/aud.