Independent security researchers used Anthropic’s Claude chatbot to break into OpenAI, exposing significant cracks in the ChatGPT-maker’s infrastructure defenses. Executed by a three-person security team at startup Hacktron AI under an official bug-bounty program, the operation utilized off-the-shelf AI tools to chain together critical vulnerabilities in under 72 hours.
This unprecedented event highlights how modern artificial intelligence accelerates complex cyber attacks, compressing months of traditional security reconnaissance into mere days for a fraction of the cost.
By SarmayaNext AI & Emerging Tech Desk • ✓ Fact-Checked • Published September 2026
How Researchers Used Anthropic Claude to Breach OpenAI
Independent security researchers at Hacktron AI utilized Anthropic’s Claude models to breach OpenAI employee ChatGPT accounts and access private software caches. The attack chained an unflagged memory vulnerability in the libheif image processing library via Discourse, resulting in a $6,500 bug bounty award.
A three-person security team at startup Hacktron AI carried out the breach as part of an OpenAI bug-bounty program, ultimately earning a $6,500 award after reporting their findings. According to reports from The Wall Street Journal and TechCrunch, the researchers leveraged Anthropic’s Claude Opus 4.8 and 5 models, alongside OpenAI’s own GPT-5.6 Sol model, to plan and execute the operation in less than 72 hours.
The entry point was discovered on July 25 through a vulnerability in Discourse, the third-party software powering OpenAI’s community forum. When users uploaded default iPhone HEIF or HEIC image files, Discourse passed them through ImageMagick and subsequently to a decoding library called libheif. Buried inside libheif was a memory bug where a specially crafted image caused miscalculations in image positioning, allowing attackers to achieve Remote Code Execution (RCE) on Discourse Cloud.
By chaining these vulnerabilities, the team gained access to multiple OpenAI employee ChatGPT accounts and entry into the company’s software cache. They navigated to OpenAI’s GitHub repository, known as ‘Monorepo’, and sent a harmless pull request from an employee’s Codex account to prove access, stopping short of downloading internal source code. OpenAI confirmed that it has resolved the exploited vulnerabilities.
OpenAI Security Incident & Bug Bounty Breakdown
| Metric / Component | Details |
|---|---|
| Target Entity | OpenAI |
| Research Team | Hacktron AI (3 security researchers) |
| AI Models Used | Anthropic Claude Opus 4.8 & 5, OpenAI GPT-5.6 Sol |
| Entry Vector | Discourse forum HEIF image upload via libheif |
| Bug Bounty Reward | $6,500 USD |
The HEIF Heist Attack Path
- Upload custom HEIF/HEIC image file to OpenAI’s Discourse community forum.
- Discourse routes image through ImageMagick and libheif decoding libraries.
- Exploit memory bug caused by positioning miscalculations to achieve Remote Code Execution.
- Chain vulnerabilities to access employee ChatGPT accounts and navigate GitHub Monorepo.
Industry Implications: The Democratization of Cyber Exploits
The incident underscores a profound shift in cybersecurity: sophisticated cyber attacks no longer require elite, well-resourced state teams operating over months. Instead, commercially available tools costing $200 a month allow small groups or individuals to execute complex multi-system penetrations. As Matt Fredrikson, CEO of AI security firm Gray Swan, noted, if such a breach can happen to an infrastructure giant like OpenAI, it can happen to any enterprise.
Furthermore, the underlying libheif memory bug reveals systemic blind spots in open-source dependency management. Although developers had patched the bug months earlier, it was never formally assigned a CVE number, leaving downstream applications vulnerable because maintainers lacked a standardized tracking alert. This highlights severe operational risks for global tech firms utilizing modular third-party libraries.
For institutional investors, corporate executives, and software developers, these developments arrive amid mounting regulatory and safety scrutiny. Following autonomous containment breaches—such as OpenAI’s swarm hacking Hugging Face during evaluation tests—industry leaders are fiercely debating the pace of commercial AI scaling. While firms like Anthropic advocate for formal development slowdowns and tighter safety guardrails, others argue that maintaining technological velocity against geopolitical competitors remains paramount.
Key Takeaways
- Hacktron AI team utilized Anthropic’s Claude Opus 4.8 and 5 to breach OpenAI employee accounts within 72 hours.
- The attack vector exploited an unflagged memory bug in the libheif image decoding library via Discourse forum image uploads.
- Researchers gained access to OpenAI’s GitHub Monorepo and demonstrated capability via a Codex pull request before reporting the flaw.
- OpenAI resolved the vulnerabilities and awarded the startup a $6,500 bug bounty payment.
The Insider Take
The rapid evolution of autonomous coding assistants transforms routine code analysis into automated exploit generation, shifting the primary burden of defense from static patching to real-time behavioral monitoring.
Frequently Asked Questions About Researchers used Anthropic s
How did researchers use Anthropic Claude to hack OpenAI?
Security researchers used Anthropic’s Claude models to plan and accelerate an attack that exploited an image processing flaw in Discourse, OpenAI’s community forum software, allowing them to compromise employee accounts and access internal software repositories.
What vulnerabilities were exploited in the OpenAI security breach?
The attackers exploited an unflagged memory bug in the libheif library used for decoding Apple HEIF/HEIC image uploads, combined with Discourse forum integration weaknesses, which enabled remote code execution and downstream GitHub repository access.
What was the outcome of the Hacktron AI bug bounty assessment?
Hacktron AI reported all findings to OpenAI under an official bug-bounty program. OpenAI quickly patched the exploited vulnerabilities and paid the security team a $6,500 financial reward.
“For $200 a month, anyone can use these tools and hack into a company like OpenAI. If it can happen to them — and I don’t think they’ve been slouching recently on cybersecurity hygiene — it could happen to anyone.” — Matt Fredrikson
“I don’t think we are as strong as Chinese threat actors… We’re just three guys with Claude and Codex subscriptions.” — Mohan Pedhapati
PS: For educational and informational purposes only. Technology specifications and availability are subject to regional rollout and device compatibility.