diff --git a/gitnexus/src/cli/wiki.ts b/gitnexus/src/cli/wiki.ts
index ac626fe809..70ab00785b 100644
--- a/gitnexus/src/cli/wiki.ts
+++ b/gitnexus/src/cli/wiki.ts
@@ -7,7 +7,7 @@
 
 import path from 'path';
 import readline from 'readline';
-import { execSync } from 'child_process';
+import { execSync, execFileSync } from 'child_process';
 import cliProgress from 'cli-progress';
 import { getGitRoot, isGitRepo } from '../storage/git.js';
 import { getStoragePaths, loadMeta, loadCLIConfig, saveCLIConfig } from '../storage/repo-manager.js';
@@ -343,10 +343,11 @@ function hasGhCLI(): boolean {
 
 function publishGist(htmlPath: string): { url: string; rawUrl: string } | null {
   try {
-    const output = execSync(
-      `gh gist create "${htmlPath}" --desc "Repository Wiki — generated by GitNexus" --public`,
-      { encoding: 'utf-8', stdio: ['pipe', 'pipe', 'pipe'] },
-    ).trim();
+    const output = execFileSync('gh', [
+      'gist', 'create', htmlPath,
+      '--desc', 'Repository Wiki — generated by GitNexus',
+      '--public',
+    ], { encoding: 'utf-8', stdio: ['pipe', 'pipe', 'pipe'] }).trim();
 
     // gh gist create prints the gist URL as the last line
     const lines = output.split('\n');
diff --git a/gitnexus/src/core/wiki/generator.ts b/gitnexus/src/core/wiki/generator.ts
index 29a16a5419..666dc6e463 100644
--- a/gitnexus/src/core/wiki/generator.ts
+++ b/gitnexus/src/core/wiki/generator.ts
@@ -12,7 +12,7 @@
 
 import fs from 'fs/promises';
 import path from 'path';
-import { execSync } from 'child_process';
+import { execSync, execFileSync } from 'child_process';
 
 import {
   initWikiDb,
@@ -712,8 +712,8 @@ export class WikiGenerator {
 
   private getChangedFiles(fromCommit: string, toCommit: string): string[] {
     try {
-      const output = execSync(
-        `git diff ${fromCommit}..${toCommit} --name-only`,
+      const output = execFileSync(
+        'git', ['diff', `${fromCommit}..${toCommit}`, '--name-only'],
         { cwd: this.repoPath },
       ).toString().trim();
       return output ? output.split('\n').filter(Boolean) : [];
diff --git a/gitnexus/src/mcp/local/local-backend.ts b/gitnexus/src/mcp/local/local-backend.ts
index 8c721b6466..608a17a379 100644
--- a/gitnexus/src/mcp/local/local-backend.ts
+++ b/gitnexus/src/mcp/local/local-backend.ts
@@ -1029,30 +1029,30 @@ export class LocalBackend {
     await this.ensureInitialized(repo.id);
     
     const scope = params.scope || 'unstaged';
-    const { execSync } = await import('child_process');
-    
-    // Build git diff command based on scope
-    let diffCmd: string;
+    const { execFileSync } = await import('child_process');
+
+    // Build git diff args based on scope (using execFileSync to avoid shell injection)
+    let diffArgs: string[];
     switch (scope) {
       case 'staged':
-        diffCmd = 'git diff --staged --name-only';
+        diffArgs = ['diff', '--staged', '--name-only'];
         break;
       case 'all':
-        diffCmd = 'git diff HEAD --name-only';
+        diffArgs = ['diff', 'HEAD', '--name-only'];
         break;
       case 'compare':
         if (!params.base_ref) return { error: 'base_ref is required for "compare" scope' };
-        diffCmd = `git diff ${params.base_ref} --name-only`;
+        diffArgs = ['diff', params.base_ref, '--name-only'];
         break;
       case 'unstaged':
       default:
-        diffCmd = 'git diff --name-only';
+        diffArgs = ['diff', '--name-only'];
         break;
     }
-    
+
     let changedFiles: string[];
     try {
-      const output = execSync(diffCmd, { cwd: repo.repoPath, encoding: 'utf-8' });
+      const output = execFileSync('git', diffArgs, { cwd: repo.repoPath, encoding: 'utf-8' });
       changedFiles = output.trim().split('\n').filter(f => f.length > 0);
     } catch (err: any) {
       return { error: `Git diff failed: ${err.message}` };
@@ -1226,9 +1226,15 @@ export class LocalBackend {
     
     // Simple text search across the repo for the old name (in files not already covered by graph)
     try {
-      const { execSync } = await import('child_process');
-      const rgCmd = `rg -l --type-add "code:*.{ts,tsx,js,jsx,py,go,rs,java}" -t code "\\b${oldName}\\b" .`;
-      const output = execSync(rgCmd, { cwd: repo.repoPath, encoding: 'utf-8', timeout: 5000 });
+      const { execFileSync } = await import('child_process');
+      const rgArgs = [
+        '-l',
+        '--type-add', 'code:*.{ts,tsx,js,jsx,py,go,rs,java}',
+        '-t', 'code',
+        `\\b${oldName}\\b`,
+        '.',
+      ];
+      const output = execFileSync('rg', rgArgs, { cwd: repo.repoPath, encoding: 'utf-8', timeout: 5000 });
       const files = output.trim().split('\n').filter(f => f.length > 0);
       
       for (const file of files) {
diff --git a/gitnexus/src/mcp/staleness.ts b/gitnexus/src/mcp/staleness.ts
index 0b7cf2a15e..8c044e61dd 100644
--- a/gitnexus/src/mcp/staleness.ts
+++ b/gitnexus/src/mcp/staleness.ts
@@ -5,7 +5,7 @@
  * Returns a hint for the LLM to call analyze if stale.
  */
 
-import { execSync } from 'child_process';
+import { execFileSync } from 'child_process';
 import path from 'path';
 
 export interface StalenessInfo {
@@ -20,8 +20,8 @@ export interface StalenessInfo {
 export function checkStaleness(repoPath: string, lastCommit: string): StalenessInfo {
   try {
     // Get count of commits between lastCommit and HEAD
-    const result = execSync(
-      `git rev-list --count ${lastCommit}..HEAD`,
+    const result = execFileSync(
+      'git', ['rev-list', '--count', `${lastCommit}..HEAD`],
       { cwd: repoPath, encoding: 'utf-8', stdio: ['pipe', 'pipe', 'pipe'] }
     ).trim();