diff --git a/ios/Sources/GutenbergKit/Sources/Media/MediaUploadServer.swift b/ios/Sources/GutenbergKit/Sources/Media/MediaUploadServer.swift
index 5b3c90c0b..d18cacae4 100644
--- a/ios/Sources/GutenbergKit/Sources/Media/MediaUploadServer.swift
+++ b/ios/Sources/GutenbergKit/Sources/Media/MediaUploadServer.swift
@@ -186,6 +186,10 @@ final class MediaUploadServer: Sendable {
     private static func passthroughResponse(
         _ request: HTTPServer.Request, query: String, context: UploadContext
     ) async throws -> HTTPResponse {
+        // As in `processAndUpload`: don't put bytes on the wire for a torn-down
+        // editor, regardless of whether the HTTP client honors cancellation.
+        try Task.checkCancellation()
+
         Logger.uploadServer.debug("Passthrough: forwarding original request body to WordPress")
         guard let body = request.parsed.body,
               let contentType = request.parsed.header("Content-Type"),
@@ -313,6 +317,13 @@ final class MediaUploadServer: Sendable {
             }
         }
 
+        // The editor was torn down (or the client disconnected) while we processed.
+        // Don't start an outbound upload whose response nobody will read — it would
+        // create an attachment neither GutenbergKit nor the host knows to clean up.
+        // Checking here rather than relying on the HTTP client to notice cancellation
+        // keeps this true for a host-injected `URLSessionProtocol` that doesn't.
+        try Task.checkCancellation()
+
         // Step 2: Upload to remote WordPress
         if let delegate = context.uploadDelegate,
            let result = try await delegate.uploadFile(at: uploadURL, mimeType: uploadMimeType, filename: uploadFilename) {