diff --git a/packages/cli/src/config/extensions/github_fetch.test.ts b/packages/cli/src/config/extensions/github_fetch.test.ts
index fe6edbedb28..a7b0c9f92c9 100644
--- a/packages/cli/src/config/extensions/github_fetch.test.ts
+++ b/packages/cli/src/config/extensions/github_fetch.test.ts
@@ -104,6 +104,60 @@ describe('fetchJson', () => {
     ).resolves.toEqual({ permanent: true });
   });
 
+  it('should not include Authorization header when redirected to a different host', async () => {
+    process.env['GITHUB_TOKEN'] = 'secret-token';
+
+    // First request to github.com redirects to an external host
+    getMock.mockImplementationOnce((_url, options, callback) => {
+      expect((options.headers as Record<string, string>)['Authorization']).toBe(
+        'token secret-token',
+      );
+      const res = new EventEmitter() as IncomingMessage;
+      res.statusCode = 302;
+      res.headers = { location: 'https://external-host.com/data' };
+      (callback as (res: IncomingMessage) => void)(res);
+      res.emit('end');
+      return new EventEmitter() as ClientRequest;
+    });
+
+    // Second request to the external host must NOT include Authorization
+    getMock.mockImplementationOnce((_url, options, callback) => {
+      expect(
+        (options.headers as Record<string, string>)['Authorization'],
+      ).toBeUndefined();
+      const res = new EventEmitter() as IncomingMessage;
+      res.statusCode = 200;
+      (callback as (res: IncomingMessage) => void)(res);
+      res.emit('data', Buffer.from('{"safe": true}'));
+      res.emit('end');
+      return new EventEmitter() as ClientRequest;
+    });
+
+    await expect(
+      fetchJson('https://api.github.com/repos/foo/bar'),
+    ).resolves.toEqual({ safe: true });
+
+    delete process.env['GITHUB_TOKEN'];
+  });
+
+  it('should reject with "Too many redirects" after 10 redirects', async () => {
+    // Each call returns a redirect to the same URL, simulating an infinite loop
+    for (let i = 0; i <= 10; i++) {
+      getMock.mockImplementationOnce((_url, _options, callback) => {
+        const res = new EventEmitter() as IncomingMessage;
+        res.statusCode = 302;
+        res.headers = { location: 'https://example.com/loop' };
+        (callback as (res: IncomingMessage) => void)(res);
+        res.emit('end');
+        return new EventEmitter() as ClientRequest;
+      });
+    }
+
+    await expect(fetchJson('https://example.com/loop')).rejects.toThrow(
+      'Too many redirects',
+    );
+  });
+
   it('should reject on non-200/30x status code', async () => {
     getMock.mockImplementationOnce((_url, _options, callback) => {
       const res = new EventEmitter() as IncomingMessage;
diff --git a/packages/cli/src/config/extensions/github_fetch.ts b/packages/cli/src/config/extensions/github_fetch.ts
index 33a9cb674fe..67cb7e1f47f 100644
--- a/packages/cli/src/config/extensions/github_fetch.ts
+++ b/packages/cli/src/config/extensions/github_fetch.ts
@@ -13,12 +13,19 @@ export function getGitHubToken(): string | undefined {
 export async function fetchJson<T>(
   url: string,
   redirectCount: number = 0,
+  trustedHostname?: string,
 ): Promise<T> {
+  const currentHostname = new URL(url).hostname;
+  // On first call, pin the trusted hostname from the initial URL.
+  // On subsequent (redirect) calls the caller passes it down so we can
+  // compare and strip the Authorization header for cross-origin redirects.
+  const trusted = trustedHostname ?? currentHostname;
+
   const headers: { 'User-Agent': string; Authorization?: string } = {
     'User-Agent': 'gemini-cli',
   };
   const token = getGitHubToken();
-  if (token) {
+  if (token && currentHostname === trusted) {
     headers.Authorization = `token ${token}`;
   }
   return new Promise((resolve, reject) => {
@@ -31,7 +38,7 @@ export async function fetchJson<T>(
           if (!res.headers.location) {
             return reject(new Error('No location header in redirect response'));
           }
-          fetchJson<T>(res.headers.location, redirectCount++)
+          fetchJson<T>(res.headers.location, redirectCount + 1, trusted)
             .then(resolve)
             .catch(reject);
           return;