diff -ruNp curl-7.19.5.orig/lib/nss.c curl-7.19.5/lib/nss.c
--- curl-7.19.5.orig/lib/nss.c	2009-07-10 13:54:34.592293130 +0200
+++ curl-7.19.5/lib/nss.c	2009-07-10 13:54:48.250293559 +0200
@@ -856,9 +856,17 @@ void Curl_nss_cleanup(void)
    * as a safety feature.
    */
   PR_Lock(nss_initlock);
+
+  /* Free references to client certificates held in the SSL session cache.
+   * Omitting this hampers destruction of the security module owning
+   * the certificates. */
+  SSL_ClearSessionCache();
+
   if (initialized) {
-    if(mod)
+    if(mod) {
+      SECMOD_UnloadUserModule(mod);
       SECMOD_DestroyModule(mod);
+    }
     mod = NULL;
     NSS_Shutdown();
   }