diff --git a/ext/zlib/zlib.c b/ext/zlib/zlib.c
index e398c26a6ed..089467018c1 100644
--- a/ext/zlib/zlib.c
+++ b/ext/zlib/zlib.c
@@ -817,6 +817,8 @@ PHP_FUNCTION(gzencode)
 			trailer[6] = (char) (stream.total_in >> 16) & 0xFF;
 			trailer[7] = (char) (stream.total_in >> 24) & 0xFF;
 			trailer[8] = '\0';
+		} else {
+			s2[stream.total_out + GZIP_HEADER_LENGTH + (coding == CODING_GZIP ? GZIP_FOOTER_LENGTH : 0)] = '\0';
 		}
 		RETURN_STRINGL(s2, stream.total_out + GZIP_HEADER_LENGTH + (coding == CODING_GZIP ? GZIP_FOOTER_LENGTH : 0), 0);
 	} else {