diff --git a/docs/changes.txt b/docs/changes.txt
index ebca103e84..730996fbaa 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -452,6 +452,7 @@ All:
 - Added wxMessageQueue::Clear().
 - Added wxConfig::Read(float *) overload (Terry Farnham).
 - Always use decimal point (and not the current locale separator) in wxConfig.
+- Fix posting of binary data using wxHTTP (Catalin Raceanu).
 
 Unix:
 
diff --git a/src/common/http.cpp b/src/common/http.cpp
index 9a4833595e..4af87f6d24 100644
--- a/src/common/http.cpp
+++ b/src/common/http.cpp
@@ -346,7 +346,17 @@ bool wxHTTP::BuildRequest(const wxString& path, wxHTTP_Req req)
     Write("\r\n", 2);
 
     if ( req == wxHTTP_POST ) {
-        Write(m_post_buf.mbc_str(), m_post_buf.Len());
+        // Post data can be arbitrary binary data when the "binary" content
+        // transfer encoding is used so don't assume it's ASCII only or
+        // NUL-terminated.
+        {
+            const wxScopedCharBuffer buf(m_post_buf.To8BitData());
+            Write(buf, buf.length());
+        } // delete the buffer before modifying the string it points to, it
+          // wouldn't really be a problem here even if we didn't do this
+          // because we won't use this buffer again but this will avoid any
+          // nasty surprises in the future if this code changes
+
         m_post_buf = wxEmptyString;
     }