fix(connect): strip Authorization on cross-origin redirects in custom Session#464
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fix(connect): strip Authorization on cross-origin redirects in custom Session#464
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The custom Session.post manually followed redirects and re-dispatched via self.request without stripping credentials, bypassing requests' SessionRedirectMixin.rebuild_auth. A malicious or compromised Connect server could return a Location header pointing to an attacker-controlled host (including protocol-relative //attacker/... resolved via urljoin) and receive the Connect API key or bootstrap JWT. Compare origins (scheme, hostname, port) between the current response URL and the resolved redirect target; on mismatch, drop any Authorization header from the outgoing headers kwarg, suppress the session-level Authorization header, and set auth=None for the next hop. Also reject redirect schemes other than http/https. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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tdstein
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Apr 9, 2026
Replace the hand-rolled redirect loop in Session.post with a minimal rebuild_method override. Inheriting from requests.SessionRedirectMixin restores rebuild_auth (strips Authorization on cross-origin hops), cookie propagation, response.history, TooManyRedirects, proxy rebuild, and streaming semantics — all of which the previous implementation silently dropped. Supersedes the defensive patch in #464.
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Summary
The custom
Session.postinsrc/posit/connect/sessions.pymanually follows redirects withallow_redirects=False, bypassingrequests.SessionRedirectMixin.rebuild_auth. On a cross-origin redirect, the session'sAuthorizationheader (Connect API key or bootstrap JWT) was forwarded to the attacker-controlled host named inLocation— including protocol-relative//attacker/...resolved viaurljoin.Authorizationfrom the outgoing headers kwarg and passesauth=Nonefor that request.http/https.preserve_postbehavior unchanged.Test plan
tests/posit/connect/test_sessions.py(12 passing):