Index: apps/app_voicemail.c
===================================================================
--- apps/app_voicemail.c	(revision 249888)
+++ apps/app_voicemail.c	(working copy)
@@ -1189,6 +1189,12 @@
 	fprintf(text_file_ptr, "%s\n", "[message]");
 
 	cid_num = get_header_by_tag(header_content, "X-Asterisk-VM-Caller-ID-Num:");
+	/* get_header_by_tag() uses a global buffer and is called below to get the cid_name
+	 * and only then both cid_num and cid_name are used; so we need to make a copy of
+	 * cid_num (if it is not NULL) to detach from the global buffer */
+	if (cid_num) {
+		cid_num = ast_strdupa(cid_num);
+	}
 	cid_name = get_header_by_tag(header_content, "X-Asterisk-VM-Caller-ID-Name:");
 	fprintf(text_file_ptr, "callerid=\"%s\" <%s>\n", S_OR(cid_name, ""), S_OR(cid_num, ""));
 	context = get_header_by_tag(header_content, "X-Asterisk-VM-Context:");