use UTC() in v4 event stream signing (#3105)

rb-kurrent · web-flow · commit 4f82369defda · 2025-06-10T12:39:06.000-04:00
diff --git a/.changelog/9f2244ae-e04a-4aeb-b2c5-3783a9ba261c.json b/.changelog/9f2244ae-e04a-4aeb-b2c5-3783a9ba261c.json
@@ -0,0 +1,9 @@
+{
+    "id": "9f2244ae-e04a-4aeb-b2c5-3783a9ba261c",
+    "type": "bugfix",
+    "description": "StreamSigner uses signingTime.UTC()",
+    "collapse": false,
+    "modules": [
+        "aws/signer/v4"
+    ]
+}
diff --git a/aws/signer/v4/stream.go b/aws/signer/v4/stream.go
@@ -59,7 +59,7 @@ func (s *StreamSigner) GetSignature(ctx context.Context, headers, payload []byte
 
 	prevSignature := s.prevSignature
 
-	st := v4Internal.NewSigningTime(signingTime)
+	st := v4Internal.NewSigningTime(signingTime.UTC())
 
 	sigKey := s.signingKeyDeriver.DeriveKey(s.credentials, s.service, s.region, st)
 
