diff --git a/rules/stellar/access-control/detect-missing-access-control.ts b/rules/stellar/access-control/detect-missing-access-control.ts
new file mode 100644
index 0000000..f713900
--- /dev/null
+++ b/rules/stellar/access-control/detect-missing-access-control.ts
@@ -0,0 +1,44 @@
+/**
+ * Detect Missing Soroban Access Control Layers (#375)
+ * Flags privileged functions that expose sensitive operations without role validation.
+ */
+
+export interface AccessControlResult {
+  detected: boolean;
+  flaggedFunctions: string[];
+  message: string;
+  suggestion: string;
+}
+
+const PRIVILEGED_PATTERNS = [
+  /fn\s+(set_admin|transfer_admin|withdraw|pause|unpause|mint|burn|upgrade)\s*\(/g,
+];
+
+const AUTH_GUARD = /require_auth|only_admin|assert_owner|has_role/;
+
+export function detectMissingAccessControl(code: string): AccessControlResult {
+  const flaggedFunctions: string[] = [];
+
+  for (const pattern of PRIVILEGED_PATTERNS) {
+    for (const match of code.matchAll(pattern)) {
+      const fnName = match[1];
+      // Extract a small window of code after the function signature to check for an auth guard
+      const startIdx = match.index ?? 0;
+      const window = code.slice(startIdx, startIdx + 300);
+      if (!AUTH_GUARD.test(window)) {
+        flaggedFunctions.push(fnName);
+      }
+    }
+  }
+
+  if (flaggedFunctions.length === 0) {
+    return { detected: false, flaggedFunctions: [], message: 'Access control present on all privileged functions.', suggestion: '' };
+  }
+
+  return {
+    detected: true,
+    flaggedFunctions,
+    message: `Privileged function(s) lack access control: ${flaggedFunctions.join(', ')}.`,
+    suggestion: 'Add `require_auth()` or an admin role check at the start of each privileged function.',
+  };
+}
diff --git a/rules/stellar/cross-contract/detect-unsafe-cross-contract-invocation.ts b/rules/stellar/cross-contract/detect-unsafe-cross-contract-invocation.ts
new file mode 100644
index 0000000..617ec50
--- /dev/null
+++ b/rules/stellar/cross-contract/detect-unsafe-cross-contract-invocation.ts
@@ -0,0 +1,45 @@
+/**
+ * Detect Unsafe Cross-Contract Invocation (#378)
+ * Flags cross-contract calls that lack caller validation or return-value checks.
+ */
+
+export interface CrossContractResult {
+  detected: boolean;
+  message: string;
+  suggestion: string;
+}
+
+const INVOCATION_PATTERNS = [
+  /invoke_contract\s*\(/,
+  /Client::new\s*\(/,
+  /env\.invoke\s*\(/,
+  /call_contract\s*\(/,
+];
+
+const VALIDATION_PATTERNS = [
+  /require_auth/,
+  /verify_contract/,
+  /\.unwrap_or_else/,
+  /\.expect\s*\(/,
+  /match\s+.*\{/,
+];
+
+export function detectUnsafeCrossContractInvocation(code: string): CrossContractResult {
+  const hasInvocation = INVOCATION_PATTERNS.some((p) => p.test(code));
+
+  if (!hasInvocation) {
+    return { detected: false, message: 'No cross-contract invocations found.', suggestion: '' };
+  }
+
+  const hasValidation = VALIDATION_PATTERNS.some((p) => p.test(code));
+
+  if (!hasValidation) {
+    return {
+      detected: true,
+      message: 'Cross-contract invocation detected without caller validation or result verification.',
+      suggestion: 'Validate the callee address and handle invocation results explicitly to prevent unexpected behaviour.',
+    };
+  }
+
+  return { detected: false, message: 'Cross-contract invocation appears guarded.', suggestion: '' };
+}
diff --git a/rules/stellar/optimization/detect-inefficient-symbol-usage.ts b/rules/stellar/optimization/detect-inefficient-symbol-usage.ts
new file mode 100644
index 0000000..382061e
--- /dev/null
+++ b/rules/stellar/optimization/detect-inefficient-symbol-usage.ts
@@ -0,0 +1,36 @@
+/**
+ * Detect Inefficient Symbol Usage (#374)
+ * Flags repeated inline Symbol construction that could be replaced with static references.
+ */
+
+export interface SymbolUsageResult {
+  detected: boolean;
+  repeated: string[];
+  message: string;
+  suggestion: string;
+}
+
+export function detectInefficientSymbolUsage(code: string): SymbolUsageResult {
+  const matches = [...code.matchAll(/Symbol::new\(\s*&env\s*,\s*["']([^"']+)["']\s*\)/g)];
+  const names = matches.map((m) => m[1]);
+
+  const counts: Record<string, number> = {};
+  for (const name of names) {
+    counts[name] = (counts[name] ?? 0) + 1;
+  }
+
+  const repeated = Object.entries(counts)
+    .filter(([, count]) => count > 1)
+    .map(([name]) => name);
+
+  if (repeated.length === 0) {
+    return { detected: false, repeated: [], message: 'No repeated symbol construction found.', suggestion: '' };
+  }
+
+  return {
+    detected: true,
+    repeated,
+    message: `Symbol(s) constructed multiple times: ${repeated.join(', ')}.`,
+    suggestion: 'Define symbols as constants or lazy statics to avoid repeated allocation overhead.',
+  };
+}
diff --git a/rules/stellar/upgradeability/detect-missing-upgrade-guards.ts b/rules/stellar/upgradeability/detect-missing-upgrade-guards.ts
new file mode 100644
index 0000000..3e77cca
--- /dev/null
+++ b/rules/stellar/upgradeability/detect-missing-upgrade-guards.ts
@@ -0,0 +1,33 @@
+/**
+ * Detect Missing Contract Upgrade Guards (#373)
+ * Flags upgrade functions that lack admin/owner validation.
+ */
+
+export interface UpgradeGuardResult {
+  detected: boolean;
+  message: string;
+  suggestion: string;
+}
+
+const UPGRADE_PATTERNS = [/fn\s+upgrade\s*\(/, /fn\s+update_contract\s*\(/, /fn\s+set_wasm\s*\(/];
+const AUTH_PATTERNS = [/require_auth/, /admin\.require_auth/, /only_admin/, /assert_admin/];
+
+export function detectMissingUpgradeGuards(code: string): UpgradeGuardResult {
+  const hasUpgradeMethod = UPGRADE_PATTERNS.some((p) => p.test(code));
+
+  if (!hasUpgradeMethod) {
+    return { detected: false, message: 'No upgrade methods found.', suggestion: '' };
+  }
+
+  const hasAuthCheck = AUTH_PATTERNS.some((p) => p.test(code));
+
+  if (!hasAuthCheck) {
+    return {
+      detected: true,
+      message: 'Upgrade method detected without admin authorization guard.',
+      suggestion: 'Add `admin.require_auth()` or an equivalent role check before allowing contract upgrades.',
+    };
+  }
+
+  return { detected: false, message: 'Upgrade guard present.', suggestion: '' };
+}