Reported by 2 outlets

Timeline

1. original reporting

   AI-Built Exploit and Sign-In Flaw Opened Path to Internal OpenAI Code

   securityweek.com · 25d ago · September 18th, 2026

   Researchers at security firm Hacktron used Claude to build a working exploit for a vulnerability in an image-processing library, then chained it with a flaw in OpenAI’s sign-in system to take over employee ChatGPT and Codex accounts, and ultimately gained access to internal code repositories. The entry point was OpenAI’s community forum, community.openai.com, which runs on Discourse. Discourse’s built-in image checks didn’t support the HEIC/HEIF photo format, so uploads in that format were passed to ImageMagick, exposing an unpatched flaw in the libheif library it relies on for decoding. Hacktron says the underlying bug had been fixed upstream a year earlier without ever being flagged as a security issue, so it was never assigned a CVE and missed the usual patching cycle. Turning the flaw into a reliable exploit took several attempts and involved Claude Opus 4.8 and Opus 5. The exploit allowed remote code execution, which the researchers first used against a test Discourse instance, then on OpenAI’s own forum. Because the forum let people sign in with their OpenAI account, code execution there opened a path to broader account access. Hacktron says that until the issue was fixed, any user or employee who logged into the forum could have had their ChatGPT and Codex accounts taken over. In addition, since people often connect other services to those accounts, the theoretical exposure extended to services like GitHub, Slack and email. Op

2. update from cyberscoop.com

   Researchers use AI to find widespread software decoder flaw

   cyberscoop.com · 25d ago · September 18th, 2026

   Researchers said they used Anthropic’s Claude and OpenAI’s Codex to identify a damaging flaw embedded in a popular software decoding tool that could leave major internet platforms, enterprise services, and web frameworks vulnerable to data theft and remote access. The vulnerability, nicknamed HEIF Heist, refers to the malware’s ability to trigger memory corruption errors in affected software, allowing the attacker to pilfer sensitive data from its victims. In a report published Thursday, the researchers laid out the potential damage an attacker could cause, including gaining access to internal OpenAI repositories, leaking user files, access tokens, and other sensitive data for online services like Amazon Web Services, and gaining remote code execution privileges across a range of online services, including Meta’s core product suite, GitHub Enterprise servers and open-source internet forum Discourse. “Even when Remote Code Execution isn’t immediately achievable, the attack primitives may still allow arbitrary heap disclosure, letting an attacker ‘heist’ in-memory data such as other users’ data and environment variables,” wrote Hacktron researchers Harsh Jaiswal, Mohan SRK, Rahul Maini and Sudhanshu Rajbhar. The researchers relied heavily on AI systems, including frontier models from OpenAI and Anthropic, to conduct their research . Attribution for the research is described as being “led” by the Hacktron human researchers “assisted by Hacktron Harness, GPT-5.6 Sol, and Opus 5.”

3. update from securityweek.com

   OpenAI Internal Code Accessed Via AI-Generated Exploit and Sign-In Vulnerability

   securityweek.com · 24d ago · September 20th, 2026

   A cybersecurity incident allowed unauthorized access to OpenAI's internal code, reportedly facilitated by an AI-built exploit and a sign-in flaw. This event underscores the evolving threat landscape where AI can be weaponized to create sophisticated attack vectors, presenting new challenges for securing critical technology infrastructure and highlighting potential vulnerabilities in advanced AI development environments. submitted by /u/Perfect-Ride-5487 [link] [comments]

   via reddit r/cybersecurity: OpenAI Internal Code Accessed Via AI-Generated Exploit and Sign-In Vulnerability