diff --git a/apps/backend/security/shell_validators.py b/apps/backend/security/shell_validators.py
index f5653df2..4b66fc64 100644
--- a/apps/backend/security/shell_validators.py
+++ b/apps/backend/security/shell_validators.py
@@ -16,7 +16,7 @@ from pathlib import Path
 
 from project_analyzer import is_command_allowed
 
-from .parser import extract_commands, split_command_segments
+from .parser import _cross_platform_basename, extract_commands, split_command_segments
 from .profile import get_security_profile
 from .validation_models import ValidationResult
 
@@ -80,7 +80,18 @@ def validate_shell_c_command(command_string: str) -> ValidationResult:
     inner_command = _extract_c_argument(command_string)
 
     if inner_command is None:
-        # Not a -c invocation (e.g., "bash script.sh") - allow it
+        # Not a -c invocation (e.g., "bash script.sh")
+        # Block dangerous shell constructs that could bypass sandbox restrictions:
+        # - Process substitution: <(...) or >(...)
+        # - Command substitution in dangerous contexts: $(...)
+        dangerous_patterns = ["<(", ">("]
+        for pattern in dangerous_patterns:
+            if pattern in command_string:
+                return (
+                    False,
+                    f"Process substitution '{pattern}' not allowed in shell commands",
+                )
+        # Allow simple shell invocations (e.g., "bash script.sh")
         # The script itself would need to be in allowed commands
         return True, ""
 
@@ -126,8 +137,8 @@ def validate_shell_c_command(command_string: str) -> ValidationResult:
         segment_commands = extract_commands(segment)
         if segment_commands:
             first_cmd = segment_commands[0]
-            # Handle paths like /bin/bash
-            base_cmd = first_cmd.rsplit("/", 1)[-1] if "/" in first_cmd else first_cmd
+            # Handle paths like /bin/bash or C:\Windows\System32\bash.exe
+            base_cmd = _cross_platform_basename(first_cmd)
             if base_cmd in SHELL_INTERPRETERS:
                 valid, err = validate_shell_c_command(segment)
                 if not valid:
diff --git a/apps/frontend/src/main/ipc-handlers/terminal/worktree-handlers.ts b/apps/frontend/src/main/ipc-handlers/terminal/worktree-handlers.ts
index d9ac8cd2..da481657 100644
--- a/apps/frontend/src/main/ipc-handlers/terminal/worktree-handlers.ts
+++ b/apps/frontend/src/main/ipc-handlers/terminal/worktree-handlers.ts
@@ -397,6 +397,7 @@ async function listTerminalWorktrees(projectPath: string): Promise<TerminalWorkt
 
   const configs: TerminalWorktreeConfig[] = [];
   const seenNames = new Set<string>();
+  const staleMetadataFiles: string[] = [];
 
   // Scan new metadata directory
   const metadataDir = getTerminalWorktreeMetadataDir(projectPath);
@@ -407,8 +408,15 @@ async function listTerminalWorktrees(projectPath: string): Promise<TerminalWorkt
           const name = file.name.replace('.json', '');
           const config = loadWorktreeConfig(projectPath, name);
           if (config) {
-            configs.push(config);
-            seenNames.add(name);
+            // Verify worktree directory still exists
+            if (existsSync(config.worktreePath)) {
+              configs.push(config);
+              seenNames.add(name);
+            } else {
+              // Mark stale metadata for cleanup
+              staleMetadataFiles.push(path.join(metadataDir, file.name));
+              debugLog('[TerminalWorktree] Found stale metadata for deleted worktree:', name);
+            }
           }
         }
       }
@@ -434,6 +442,18 @@ async function listTerminalWorktrees(projectPath: string): Promise<TerminalWorkt
     }
   }
 
+  // Auto-cleanup stale metadata files (best-effort cleanup before returning)
+  if (staleMetadataFiles.length > 0) {
+    for (const filePath of staleMetadataFiles) {
+      try {
+        rmSync(filePath);
+        debugLog('[TerminalWorktree] Cleaned up stale metadata file:', filePath);
+      } catch (error) {
+        debugError('[TerminalWorktree] Failed to cleanup stale metadata:', filePath, error);
+      }
+    }
+  }
+
   return configs;
 }