[API] Baggage - Trim white spaces and check for semi colon which isn't allowed octet

src/OpenTelemetry.Api/CHANGELOG.md

@@ -12,6 +12,15 @@ Notes](../../RELEASENOTES.md).
   sensitive.
   ([#6931](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6931))
 
+* Fixed `BaggagePropagator` to trim optional whitespace (OWS) around `=`
+  separators when parsing the `baggage` header, as required by the
+  [W3C Baggage specification](https://www.w3.org/TR/baggage/).
+  ([#7009](https://github.com/open-telemetry/opentelemetry-dotnet/pull/7009))
+
+* Fixed `BaggagePropagator` to strip baggage properties (e.g. `;metadata`)
+  from values when parsing the `baggage` header.
+  ([#7009](https://github.com/open-telemetry/opentelemetry-dotnet/pull/7009))
+
 ## 1.15.0
 
 Released 2026-Jan-21

src/OpenTelemetry.Api/Context/Propagation/BaggagePropagator.cs

@@ -160,8 +160,21 @@ internal static bool TryExtractBaggage(
                     continue;
                 }
 
-                var key = WebUtility.UrlDecode(parts[0]);
-                var value = WebUtility.UrlDecode(parts[1]);
+                var rawValue = parts[1];
+
+                // semicolon is not a valid baggage-octet
+#if NET
+                var semicolonIndex = rawValue.IndexOf(';', StringComparison.Ordinal);
+#else
+                var semicolonIndex = rawValue.IndexOf(';');
+#endif
+                if (semicolonIndex >= 0)
+                {
+                    rawValue = rawValue.Substring(0, semicolonIndex);
+                }
+
+                var key = WebUtility.UrlDecode(parts[0].Trim());
+                var value = WebUtility.UrlDecode(rawValue.Trim());
 
                 if (string.IsNullOrEmpty(key) || string.IsNullOrEmpty(value))
                 {

test/OpenTelemetry.Api.Tests/Context/Propagation/BaggagePropagatorTests.cs

@@ -238,7 +238,7 @@ public void ValidateEmptyValueSkipped()
         Assert.Empty(propagationContext.Baggage.GetBaggage());
     }
 
-    [Fact(Skip = "Fails due to spec mismatch, tracked in https://github.com/open-telemetry/opentelemetry-dotnet/issues/5210")]
+    [Fact]
     public void ValidateOWSOnExtraction()
     {
         var carrier = new Dictionary<string, string>
@@ -259,7 +259,7 @@ public void ValidateOWSOnExtraction()
         Assert.Equal("SomeValue2", baggage[1].Value);
     }
 
-    [Fact(Skip = "Fails due to spec mismatch, tracked in https://github.com/open-telemetry/opentelemetry-dotnet/issues/5210")]
+    [Fact]
     public void ValidateSemicolonMetadataIgnoredOnExtraction()
     {
         var carrier = new Dictionary<string, string>
@@ -276,6 +276,39 @@ public void ValidateSemicolonMetadataIgnoredOnExtraction()
         Assert.Equal("SomeValue", baggage.Value);
     }
 
+    [Fact]
+    public void ValidateOptionalWhiteSpaceExtractionDoesNotCorruptOnReinjection()
+    {
+        // Simulates a header emitted by .NET 10's W3C propagator
+        var carrier = new Dictionary<string, string>
+        {
+            { BaggagePropagator.BaggageHeaderName, "correlationId = 12345, userId = user-abc" },
+        };
+
+        var extractedContext = this.baggage.Extract(default, carrier, Getter);
+
+        var outboundCarrier = new Dictionary<string, string>();
+        this.baggage.Inject(extractedContext, outboundCarrier, Setter);
+
+        Assert.Equal("correlationId=12345,userId=user-abc", outboundCarrier[BaggagePropagator.BaggageHeaderName]);
+    }
+
+    [Fact]
+    public void ValidateOptionalWhiteSpaceBeforeSemicolonIgnored()
+    {
+        var carrier = new Dictionary<string, string>
+        {
+            { BaggagePropagator.BaggageHeaderName, "SomeKey=SomeValue ; propertyKey=propertyValue" },
+        };
+
+        var propagationContext = this.baggage.Extract(default, carrier, Getter);
+
+        var baggage = Assert.Single(propagationContext.Baggage.GetBaggage());
+
+        Assert.Equal("SomeKey", baggage.Key);
+        Assert.Equal("SomeValue", baggage.Value);
+    }
+
     [Fact]
     public void ValidatePercentEncoding()
     {