fix(cors): reflect request origin when credentials is true with wildcard#4813
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Per the Fetch spec, Access-Control-Allow-Origin must not be '*' when credentials mode is 'include'. Browsers reject these responses. When origin is '*' and credentials is true, reflect the actual request origin instead of the wildcard. Also set Vary: Origin in this case since the response now varies by request origin. Fixes #4811
yusukebe
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Mar 20, 2026
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yusukebe
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@ctonneslan Can you add proper tests?
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #4813 +/- ##
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Coverage 92.83% 92.84%
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Files 177 177
Lines 11642 11643 +1
Branches 3466 3468 +2
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+ Hits 10808 10810 +2
+ Misses 833 832 -1
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Cover the case where origin: '*' and credentials: true should reflect the request Origin header instead of sending *.
Author
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Added tests. Three cases covering the credentials + wildcard origin behavior:
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Member
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@ctonneslan Thanks! |
This was referenced Mar 23, 2026
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Summary
Fixes the CORS middleware sending
Access-Control-Allow-Origin: *together withAccess-Control-Allow-Credentials: true, which browsers reject per the Fetch spec.Problem
When configured with
origin: '*'andcredentials: true:The middleware sets both:
Access-Control-Allow-Origin: *Access-Control-Allow-Credentials: trueThe Fetch spec requires that
Access-Control-Allow-Originmust not be*when credentials mode isinclude. Browsers reject these responses.Fix
When
credentialsis true and origin is'*', reflect the actual requestOriginheader instead of the wildcard. Also setVary: Originsince the response now varies by request.This matches the behavior of other CORS libraries (e.g., Express cors middleware).
Fixes #4811