diff --git a/CHANGELOG b/CHANGELOG
index 93b64896..58ef43f7 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -72,6 +72,10 @@ HISTORY
 
   ++ Bugfixes:
 
+  2009-02-18 Simon Goldschmidt (Jonathan Larmour and Bill Auerbach)
+  * ip_frag.c: patch #6528: the buffer used for IP_FRAG_USES_STATIC_BUF could be
+    too small depending on MEM_ALIGNMENT
+
   2009-02-16 Simon Goldschmidt
   * sockets.h/.c, api_*.h/.c: fixed arguments of socket functions to match the standard;
     converted size argument of netconn_write to 'size_t'
diff --git a/src/core/ipv4/ip_frag.c b/src/core/ipv4/ip_frag.c
index b3f8ebd4..1939d831 100644
--- a/src/core/ipv4/ip_frag.c
+++ b/src/core/ipv4/ip_frag.c
@@ -608,7 +608,7 @@ nullreturn:
 
 #if IP_FRAG
 #if IP_FRAG_USES_STATIC_BUF
-static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU)];
+static u8_t buf[LWIP_MEM_ALIGN_SIZE(IP_FRAG_MAX_MTU + MEM_ALIGNMENT - 1)];
 #endif /* IP_FRAG_USES_STATIC_BUF */
 
 /**