diff --git a/include/haproxy/pattern-t.h b/include/haproxy/pattern-t.h
index aa77c9a..b5b4d0b 100644
--- a/include/haproxy/pattern-t.h
+++ b/include/haproxy/pattern-t.h
@@ -69,6 +69,7 @@
 /* possible flags for patterns storage */
 enum {
 	PAT_SF_TREE        = 1 << 0,       /* some patterns are arranged in a tree */
+	PAT_SF_REGFREE     = 1 << 1,       /* run regex_free() on the pointer */
 };
 
 /* ACL match methods */
diff --git a/src/pattern.c b/src/pattern.c
index e4a1e27..5c83a5c 100644
--- a/src/pattern.c
+++ b/src/pattern.c
@@ -1240,6 +1240,7 @@
 	memcpy(&patl->pat, pat, sizeof(*pat));
 
 	/* compile regex */
+	patl->pat.sflags |= PAT_SF_REGFREE;
 	if (!(patl->pat.ptr.reg = regex_comp(pat->ptr.str, !(expr->mflags & PAT_MF_IGNORE_CASE),
 	                                     cap, err))) {
 		free(patl);