diff --git a/quiche/quic/core/quic_linux_socket_utils_test.cc b/quiche/quic/core/quic_linux_socket_utils_test.cc
index 9c45662..f38df83 100644
--- a/quiche/quic/core/quic_linux_socket_utils_test.cc
+++ b/quiche/quic/core/quic_linux_socket_utils_test.cc
@@ -142,7 +142,7 @@
   for (bool is_ipv4 : {true, false}) {
     QuicIpAddress self_addr =
         is_ipv4 ? QuicIpAddress::Loopback4() : QuicIpAddress::Loopback6();
-    char cbuf[kCmsgSpaceForIp + kCmsgSpaceForTTL];
+    alignas(cmsghdr) char cbuf[kCmsgSpaceForIp + kCmsgSpaceForTTL];
     QuicMsgHdr quic_hdr(packet_buf, sizeof(packet_buf), peer_addr, cbuf,
                         sizeof(cbuf));
     msghdr* hdr = const_cast<msghdr*>(quic_hdr.hdr());