1 files changed, 2 insertions, 2 deletions
diff --git a/common/network/TcpSocket.cxx b/common/network/TcpSocket.cxx
index 3f2f0f1f..38cb6eb3 100644
--- a/common/network/TcpSocket.cxx
+++ b/common/network/TcpSocket.cxx
@@ -663,8 +663,8 @@ TcpFilter::Pattern TcpFilter::parsePattern(const char* p) {
   family = pattern.address.u.sa.sa_family;
 
   if (pattern.prefixlen > (family == AF_INET ? 32: 128))
-    throw Exception("invalid prefix length for filter address: %u",
-                    pattern.prefixlen);
+    throw Exception(rfb::format("invalid prefix length for filter address: %u",
+                                pattern.prefixlen));
 
   // Compute mask from address and prefix length
   memset (&pattern.mask, 0, sizeof (pattern.mask));