diff --git a/crypto/ts/ts_rsp_sign.c b/crypto/ts/ts_rsp_sign.c
index ba69cbece2..e1f187995b 100644
--- a/crypto/ts/ts_rsp_sign.c
+++ b/crypto/ts/ts_rsp_sign.c
@@ -57,6 +57,7 @@ static ASN1_INTEGER *def_serial_cb(struct TS_resp_ctx *ctx, void *data)
     TSerr(TS_F_DEF_SERIAL_CB, ERR_R_MALLOC_FAILURE);
     TS_RESP_CTX_set_status_info(ctx, TS_STATUS_REJECTION,
                                 "Error during serial number generation.");
+    ASN1_INTEGER_free(serial);
     return NULL;
 }