diff --git a/package-lock.json b/package-lock.json
index e12e659..947ce57 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -248,9 +248,9 @@
       }
     },
     "node_modules/@isaacs/brace-expansion": {
-      "version": "5.0.0",
-      "resolved": "https://registry.npmjs.org/@isaacs/brace-expansion/-/brace-expansion-5.0.0.tgz",
-      "integrity": "sha512-ZT55BDLV0yv0RBm2czMiZ+SqCGO7AvmOM3G/w2xhVPH+te0aKgFjmBvGlL1dH+ql2tgGO3MVrbb3jCKyvpgnxA==",
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/@isaacs/brace-expansion/-/brace-expansion-5.0.1.tgz",
+      "integrity": "sha512-WMz71T1JS624nWj2n2fnYAuPovhv7EUhk69R6i9dsVyzxt5eM3bjwvgk9L+APE1TRscGysAVMANkB0jh0LQZrQ==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
@@ -2467,13 +2467,13 @@
       }
     },
     "node_modules/jws": {
-      "version": "3.2.2",
-      "resolved": "https://registry.npmjs.org/jws/-/jws-3.2.2.tgz",
-      "integrity": "sha512-YHlZCB6lMTllWDtSPHz/ZXTsi8S00usEV6v1tjq8tOUZzw7DpSDWVXjXDre6ed1w/pd495ODpHZYSdkRTsa0HA==",
+      "version": "3.2.3",
+      "resolved": "https://registry.npmjs.org/jws/-/jws-3.2.3.tgz",
+      "integrity": "sha512-byiJ0FLRdLdSVSReO/U4E7RoEyOCKnEnEPMjq3HxWtvzLsV08/i5RQKsFVNkCldrCaPr2vDNAOMsfs8T/Hze7g==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
-        "jwa": "^1.4.1",
+        "jwa": "^1.4.2",
         "safe-buffer": "^5.0.1"
       }
     },
@@ -2521,9 +2521,9 @@
       }
     },
     "node_modules/lodash": {
-      "version": "4.17.21",
-      "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.21.tgz",
-      "integrity": "sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg==",
+      "version": "4.17.23",
+      "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.23.tgz",
+      "integrity": "sha512-LgVTMpQtIopCi79SJeDiP0TfWi5CNEc/L/aRdTh3yIvmZXTnheWpKjSZhnvMl8iXbC1tFg9gdHHDMLoV7CnG+w==",
       "dev": true,
       "license": "MIT"
     },
@@ -3166,9 +3166,9 @@
       }
     },
     "node_modules/qs": {
-      "version": "6.14.0",
-      "resolved": "https://registry.npmjs.org/qs/-/qs-6.14.0.tgz",
-      "integrity": "sha512-YWWTjgABSKcvs/nWBi9PycY/JiPJqOD4JA6o9Sej2AtvSGarXxKC3OQSk4pAarbdQlKAh5D4FCQkJNkW+GAn3w==",
+      "version": "6.14.1",
+      "resolved": "https://registry.npmjs.org/qs/-/qs-6.14.1.tgz",
+      "integrity": "sha512-4EK3+xJl8Ts67nLYNwqw/dsFVnCf+qR7RgXSK9jEEm9unao3njwMDdmsdvoKBKHzxd7tCYz5e5M+SnMjdtXGQQ==",
       "dev": true,
       "license": "BSD-3-Clause",
       "dependencies": {
@@ -4083,9 +4083,9 @@
       "license": "MIT"
     },
     "node_modules/undici": {
-      "version": "7.13.0",
-      "resolved": "https://registry.npmjs.org/undici/-/undici-7.13.0.tgz",
-      "integrity": "sha512-l+zSMssRqrzDcb3fjMkjjLGmuiiK2pMIcV++mJaAc9vhjSGpvM7h43QgP+OAMb1GImHmbPyG2tBXeuyG5iY4gA==",
+      "version": "7.20.0",
+      "resolved": "https://registry.npmjs.org/undici/-/undici-7.20.0.tgz",
+      "integrity": "sha512-MJZrkjyd7DeC+uPZh+5/YaMDxFiiEEaDgbUSVMXayofAkDWF1088CDo+2RPg7B1BuS1qf1vgNE7xqwPxE0DuSQ==",
       "dev": true,
       "license": "MIT",
       "engines": {
diff --git a/src/core/config.ts b/src/core/config.ts
index 107da94..b005f7a 100644
--- a/src/core/config.ts
+++ b/src/core/config.ts
@@ -137,6 +137,12 @@ export class PawnProConfigManager {
     const current = readJsonFile(filePath) ?? {};
 
     const parts = dotPath.split('.');
+    // Guard against prototype pollution
+    const forbidden = ['__proto__', 'constructor', 'prototype'];
+    if (parts.some(p => forbidden.includes(p))) {
+      throw new Error('Invalid config key: prototype pollution attempt');
+    }
+
     let cursor: Record<string, unknown> = current;
     for (let i = 0; i < parts.length - 1; i++) {
       const key = parts[i];