diff --git a/codeconcat/utils/security.py b/codeconcat/utils/security.py
index 49f1f23..12a4cfe 100644
--- a/codeconcat/utils/security.py
+++ b/codeconcat/utils/security.py
@@ -42,7 +42,7 @@ class PathValidator:
 
     # Dangerous path patterns
     DANGEROUS_PATTERNS = [
-        r"\.\.",  # Parent directory
+        r"(?:^|[\\/])\.\.(?:[\\/]|$)",  # Parent directory as path component (../foo, foo/.., etc.)
         r"~",  # Home directory
         r"\$",  # Environment variables
         r"%",  # Windows environment variables