diff --git a/.version_history b/.version_history
index 9e71a2c..afbb225 100644
--- a/.version_history
+++ b/.version_history
@@ -22,3 +22,4 @@
 a670de0f,d271b84,refactor/extract-health-routes-and-server-core,2025-09-05T17:25:09Z,michael,git,lua-api
 a670de0f,25a709e,feature/pid-file-service-management,2025-09-05T20:30:13Z,michael,git,lua-api
 a670de0f,59f372f,feature/pid-file-service-management,2025-09-07T14:58:01Z,michael,git,lua-api
+a670de0f,683d6e5,fix/validate-config-posix-regex,2025-09-07T16:00:48Z,michael,git,lua-api
diff --git a/scripts/validate-config.sh b/scripts/validate-config.sh
index 7b59dc7..ff55f1a 100755
--- a/scripts/validate-config.sh
+++ b/scripts/validate-config.sh
@@ -24,12 +24,13 @@ if ! grep -q '^\[server\]' "$CONFIG_FILE"; then
     exit 1
 fi
 
-if ! grep -q '^port\s*=' "$CONFIG_FILE"; then
+# Fix: Use POSIX-compatible regex patterns
+if ! grep -q '^[ \t]*port[ \t]*=' "$CONFIG_FILE"; then
     echo "Error: server port not configured"
     exit 1
 fi
 
-if ! grep -q '^host\s*=' "$CONFIG_FILE"; then
+if ! grep -q '^[ \t]*host[ \t]*=' "$CONFIG_FILE"; then
     echo "Error: server host not configured"
     exit 1
 fi