Software · 2 October 2026 · 4 min read
A Twelve-Line Script Could Hijack ChatGPT on Mac: The Flaw Exposing Chats and Browsers
In brief: Security researcher Patrick Wardle of the Objective-See Foundation discovered a significant vulnerability in OpenAI's official macOS ChatGPT app, allowing unprivileged local code to take full control of the software. By chaining calls through a trusted internal script interpreter, an attacker could bypass three generations of digital signature checks to access chat histories and hijack authenticated browser sessions. OpenAI patched the issue on September 25, underscoring the growing security risks associated with high-privilege AI desktop applications.
by Team Mocchi's
In recent months, cybersecurity discussions around artificial intelligence have focused almost exclusively on frontier models developing autonomous offensive capabilities or cybercriminals weaponizing generative tools. Yet the rapid migration of AI assistants from browser tabs directly onto desktop operating systems introduces an equally dangerous attack vector: AI client software acting as an attractive, high-privilege target on the victim's local machine.
This dynamic is illustrated by a vulnerability disclosed by WIRED, discovered in OpenAI's official ChatGPT app for macOS by Patrick Wardle, security analyst at the Objective-See Foundation and longtime Apple ecosystem researcher. OpenAI quietly resolved the issue on September 25 in its system change log, with spokesperson Shane Bauer acknowledging the imperative to move faster on security hardening.
Subverting Signatures: How Twelve Lines of Code Bypassed Three Verification Layers
The architecture of the ChatGPT macOS client relies on multiple background processes communicating via local inter-process communication (IPC). To prevent malicious third-party software from dispatching unauthorized commands to the core OpenAI service, engineers implemented a digital signature validation mechanism. The safeguard verifies that incoming requests originate from authentic OpenAI binaries and climbs the process tree across three generations—checking the caller, its parent, and its grandparent process—to eliminate proxy execution vulnerabilities.
Despite this multi-tier validation model, Wardle uncovered an architectural oversight. OpenAI included a signed, fully trusted script interpreter binary designed to execute external command scripts. To bypass the security barriers, an attacker merely needed to craft a script that spawned this trusted interpreter three times recursively before issuing commands to the primary ChatGPT process. Because every link in the parentage chain resolved to a legitimately signed OpenAI binary, the security checks succeeded unconditionally. Wardle noted that the exploit was trivial to execute, requiring roughly a dozen lines of code.
The Building Manager with Keys to Every Room
The impact of such an intrusion went far beyond intercepting isolated prompts. Once in control of the ChatGPT process, unprivileged local code could extract historical conversation databases, persistent app configuration, and active authentication tokens. Furthermore, the attacker could leverage the desktop client's active interconnections to commandeer linked web browser sessions and trigger secondary system actions, masked under the legitimate identity and elevated entitlements of OpenAI's signed application.
As Wardle pointed out, agentic desktop software functions like a building manager holding master keys to every apartment on the premises: to execute screen analysis, file handling, and browser automation, these tools demand expansive operating system privileges. When that central coordinator is compromised, any low-privilege script on the workstation gains access to everything the assistant touches.
The ChatGPT patch is not an isolated incident. Wardle is scheduled to present a broader analysis of vulnerabilities across macOS AI software—including a recently remediated flaw in the dictation module of Meta's Muse assistant—at the Objective by the Sea conference this November.
Mocchi's take
This incident exposes a fundamental contradiction in the race toward agentic AI: as desktop tools expand their reach into system-level workflows, they concentrate immense administrative trust inside applications whose attack surfaces are still maturing. For companies deploying AI desktop clients across employee machines for development, operational coordination, or document analysis, these tools can no longer be treated as harmless productivity widgets. Engineering leaders must enforce strict sandboxing, uphold the principle of least privilege across OS-level entitlements, and recognize that desktop AI agents represent prime pathways toward authenticated browser sessions and enterprise data.