The Google Product Security Team has publicly launched the internal proxy PageBreak: designed for self-detection of security flaws in the company's first-party web applications. The project will pilot in November 2025 and become official in January 2026, primarily running Gemini 3.1 Pro and Gemini 3.5 Flash, with the option to switch to other models. The design goal is to scale vulnerability discovery while reducing manual verification.

Unlike scanners that only output suspicious code, PageBreak must first prove that a vulnerability is exploitable before reporting it. After the proxy formulates a hypothesis, it is handed over to a deterministic verifier, which is not AI-generated, to test real payloads in a real environment: cross-site scripting injection of JavaScript to see if the rendering framework executes it; SQL injection to modify queries and verify outputs or timing; path traversal to write files in globally readable locations and read them back through the application; remote code execution attempts to delay, write to globally writable files, or issue domain names and network requests. Google claims this process reduces false positives to nearly zero, preventing product teams from being overwhelmed by unverified tickets.

According to company disclosures, after large-scale operation, over 500 cross-site scripting vulnerabilities have been discovered in first-party web applications, including sensitive domains. In contrast, another group of hundreds of applications built on a high-security network framework found only 2 cross-site scripts as of September 4, limited to internal applications or debugging endpoints with fortified gaps.

This is not Google's first self-developed bug-hunting proxy. DeepMind and Project Zero's Big Sleep first searched for vulnerabilities in open-source libraries and Chrome's V8 and graphics stack; CodeMender used Gemini Deep Think to automatically patch, submitting 72 security fixes to upstream open source within six months, covering projects with up to 4.5 million lines of code; Chrome fixed 1,072 security flaws using proxies in milestones M149 and M150, exceeding the total of the previous 23 milestones. Mandiant's proxy vulnerability discovery suite verified over 100 high-risk flaws in two days during investigations of stolen code repositories. Gemini 3.5 Flash Cyber has been fine-tuned to focus on finding and patching vulnerabilities, limited to government and vetted partners, and has been used in internal code for Chrome, Android, Cloud, Ads, and YouTube.

The same capabilities also appear in offensive and assessment incidents. Google Threat Intelligence has previously reported that criminal groups use models to assist in discovering and weaponizing zero-day vulnerabilities. In a May assessment, Gemini, after mistakenly being given access to an external network by a test company, searched for real credentials or guessed passwords based on fictitious company names, gaining access to the systems of three real enterprises, and the model stopped itself after recognizing a non-drill environment.

In market mechanisms, this represents a shift from defensive computing power to vulnerability ticketing. Buyers include product security teams that must deliver results for first-party applications, as well as cloud and government clients looking for "provable, low false positive" scanning; sellers are Google Cloud running Gemini inference and security proxy startups that productize verifiers. Funding has shifted from manual bounties and outsourced penetration testing to model calls, sandbox payloads, and framework-level fortifications. Beneficiaries are high-security frameworks—where the same proxy found 500 vulnerabilities in ordinary applications, only 2 remain in the framework, effectively transforming security from a patch race to an architectural premium; under pressure are old scanners that charge based on piled-up false positive tickets, and chat-style tools that only output "possible vulnerabilities" without verifiers. Those who can turn vulnerabilities from suspicion into reproducible payloads will secure orders within enterprise security budgets.

Source: Public Information