diff --git a/src/http_act.c b/src/http_act.c
index f613624..0aa8a37 100644
--- a/src/http_act.c
+++ b/src/http_act.c
@@ -931,6 +931,11 @@
 		cur_arg++;
 
 		hdr = calloc(1, sizeof(*hdr));
+		if (!hdr) {
+			memprintf(err, "out of memory");
+			release_sample_expr(expr);
+			return ACT_RET_PRS_ERR;
+		}
 		hdr->next = px->req_cap;
 		hdr->name = NULL; /* not a header capture */
 		hdr->namelen = 0;