Auths: fix possible OOB write in external authenticator. Bug 2999

[exim.git] / src / src / auths / external.c

diff --git a/src/src/auths/external.c b/src/src/auths/external.c
index 7e7fca8415c8339ff3790d5188090918afecf71e..790b9815902fa8897404265fcd406d4040b1f455 100644 (file)
--- a/src/src/auths/external.c
+++ b/src/src/auths/external.c
@@ -103,7 +103,7 @@ if (expand_nmax == 0)       /* skip if rxd data */
 if (ob->server_param2)
   {
   uschar * s = expand_string(ob->server_param2);
-  auth_vars[expand_nmax] = s;
+  auth_vars[expand_nmax = 1] = s;
   expand_nstring[++expand_nmax] = s;
   expand_nlength[expand_nmax] = Ustrlen(s);
   if (ob->server_param3)