diff --git a/extern/threestudio/gradio_app.py b/extern/threestudio/gradio_app.py
index c2d32f5..724ffad 100644
--- a/extern/threestudio/gradio_app.py
+++ b/extern/threestudio/gradio_app.py
@@ -9,6 +9,8 @@
 from dataclasses import dataclass
 from datetime import datetime
 from typing import Optional
+from pathlib import Path
+import json
 
 import gradio as gr
 import numpy as np
@@ -202,7 +204,49 @@ def run(
     # manually assign the output directory, name and tag so that we know the trial directory
     name = os.path.basename(model_config[model_name]["path"]).split(".")[0]
     tag = datetime.now().strftime("@%Y%m%d-%H%M%S")
-    trial_dir = os.path.join(save_root, EXP_ROOT_DIR, name, tag)
+
+    # normalize and validate save_root to avoid using unexpected directories
+    base_root = (Path.cwd() / EXP_ROOT_DIR).resolve()
+    try:
+        candidate_root = Path(save_root).expanduser().resolve()
+        # ensure the requested root stays within the base_root
+        _ = candidate_root.relative_to(base_root)
+        safe_save_root = candidate_root
+    except Exception:
+        # fall back to the default base_root on invalid or unsafe input
+        safe_save_root = base_root
+
+    # sanitize and constrain user-provided values before constructing the command
+    # Ensure prompt is safely escaped so it cannot break the expected key="value" syntax.
+    try:
+        # json.dumps returns a double-quoted string; strip the outer quotes so we can
+        # embed it inside key="...".
+        safe_prompt_inner = json.dumps(str(prompt))[1:-1]
+    except Exception:
+        safe_prompt_inner = ""
+
+    # Constrain guidance_scale to a reasonable numeric range.
+    try:
+        safe_guidance_scale = float(guidance_scale)
+    except (TypeError, ValueError):
+        safe_guidance_scale = 0.0
+    safe_guidance_scale = max(0.0, min(100.0, safe_guidance_scale))
+
+    # Constrain seed to a 32-bit signed integer range.
+    try:
+        safe_seed = int(seed)
+    except (TypeError, ValueError):
+        safe_seed = 0
+    safe_seed = max(0, min(2147483647, safe_seed))
+
+    # Constrain max_steps to a positive integer within an upper bound.
+    try:
+        safe_max_steps = int(max_steps)
+    except (TypeError, ValueError):
+        safe_max_steps = 1
+    safe_max_steps = max(1, min(20000, safe_max_steps))
+
+    trial_dir = os.path.join(str(safe_save_root), name, tag)
     alive_path = os.path.join(trial_dir, "alive")
 
     # spawn the training process
@@ -212,12 +256,12 @@ def run(
         + [
             f'name="{name}"',
             f'tag="{tag}"',
-            f"exp_root_dir={os.path.join(save_root, EXP_ROOT_DIR)}",
+            f"exp_root_dir={str(safe_save_root)}",
             "use_timestamp=false",
-            f'system.prompt_processor.prompt="{prompt}"',
-            f"system.guidance.guidance_scale={guidance_scale}",
-            f"seed={seed}",
-            f"trainer.max_steps={max_steps}",
+            f'system.prompt_processor.prompt="{safe_prompt_inner}"',
+            f"system.guidance.guidance_scale={safe_guidance_scale}",
+            f"seed={safe_seed}",
+            f"trainer.max_steps={safe_max_steps}",
         ]
         + (
             ["checkpoint.every_n_train_steps=${trainer.max_steps}"] if save_ckpt else []