diff --git a/src/output/plugins/httpd/HttpdOutputPlugin.cxx b/src/output/plugins/httpd/HttpdOutputPlugin.cxx
index ed35c1934..fa88bdda3 100644
--- a/src/output/plugins/httpd/HttpdOutputPlugin.cxx
+++ b/src/output/plugins/httpd/HttpdOutputPlugin.cxx
@@ -161,12 +161,21 @@ HttpdOutput::ReadPage() noexcept
 
 	size_t size = 0;
 	do {
-		const auto r = encoder->Read(std::span{buffer}.subspan(size));
+		const auto b = std::span{buffer}.subspan(size);
+		const auto r = encoder->Read(b);
 		if (r.empty())
 			break;
 
 		unflushed_input = 0;
 
+		if (r.data() != b.data()) {
+			/* if the encoder did not write to the given
+			   buffer but instead returned its own buffer,
+			   we need to copy it so we have a contiguous
+			   buffer */
+			std::copy(r.begin(), r.end(), b.begin());
+		}
+
 		size += r.size();
 	} while (size < sizeof(buffer));