OpenAI GPT-6 Cyber found 81 high-severity Firefox flaws and hundreds of Linux bugs, raising new questions about AI-powered cyber risks.
OpenAI has introduced GPT-6 Cyber, a model built for security research that it says finds and fixes vulnerabilities better and stays within the limits researchers set far more reliably. These are OpenAI’s own results and evaluations, so read them as claims to check.
“We’re introducing GPT‑6 Cyber, a major leap in security research: more capable at finding and fixing vulnerabilities, and far more reliable staying within the boundaries researchers set. GPT‑6 Cyber delivers major gains on key cybersecurity benchmarks over GPT‑5.6 Cyber, including a 51% relative improvement on ExploitGym and a step function improvement when tested on staying within scope.” reads the announcement. “It is already helping to secure real-world software, uncovering and validating thousands of exploits in security-critical codebases such as Linux and Firefox.”
GPT-6 Cyber outperformed previous models in tests measuring its ability to exploit vulnerabilities. It scored 48.5%, compared with 32.1% for GPT-5.6 Cyber, and outperformed GPT-6 Astra in most cybersecurity tasks.
It also found more flaws during web penetration tests, identifying 40.3% of vulnerabilities versus 32% for Astra. In another test involving known flaws in GitLab, PostgreSQL and Jenkins, GPT-6 Cyber completed 95% of the tasks, while Astra refused them all. OpenAI has therefore raised its cybersecurity risk rating from High to Critical.
The real-world numbers are bigger. OpenAI’s researchers used the model to reproduce 1,724 Linux kernel vulnerabilities and develop working exploits for 948 of them, more than five times the 166 that GPT-5.6 Sol managed with the same research setup. Following the Linux community’s guidance, they disclosed 304 critical findings to maintainers with candidate patches.
“Developing exploits for 948 Linux kernel vulnerabilities. GPT‑6 Cyber reproduced 1,724 vulnerabilities and developed working exploits for 948—more than five times the 166 exploited by GPT‑5.6 Sol using the same research harness. Following the Linux community’s guidance, we disclosed 304 critical findings to maintainers with candidate patches and are in the process of getting other vulnerabilities fixed.” continues the announcement.
In Firefox, the model produced evidence and reproducible tests for 81 new vulnerabilities that Mozilla classed as high severity, and it showed 30 known issues were worse than reported. Mozilla began landing fixes soon after getting the reports. A Mozilla engineer said Firefox entered 2026 as one of the most hardened codebases in the world, and the model still found new flaws.
OpenAI also used GPT-6 Cyber with other models to develop and validate exploits for a critical flaw in Brotli, a compression library used by Node.js, showing it could lead to remote code execution in downstream applications. Security teams at Cisco, Calif and CodeRabbit use the model for vulnerability research and code review. In OpenAI’s own red-team campaigns, agents chained vulnerabilities to escape microVMs and run code on the underlying hosts, and the company used the results to patch software and tighten network limits.
Power like that makes scope control the key question. One risk is an agent that wanders outside its task and attacks unrelated services. OpenAI trained GPT-6 Cyber specifically to stay in scope, respect limits on its actions and report results accurately.
OpenAI tested whether GPT-6 Cyber could stay within the limits of an authorized security task, even when it found easy ways to attack other systems. The model avoided unauthorized actions in 99.93% of cases, compared with 94.49% for GPT-5.6 Cyber. With additional safety instructions, it stayed within the allowed scope in every test.
“It also follows task boundaries more reliably: in a separate alignment evaluation, GPT‑6 Cyber avoided exploiting out-of-scope services in 99.93% of tests without its deployment prompt, and 100% with this prompt.” states the AI company. “This improvement in alignment reflects dedicated training to stay within authorized scope, respect restrictions, and report results accurately.”
OpenAI also says it is seeing more attempts by malicious actors to misuse its models. To reduce this risk, the company monitors suspicious activity, checks whether actions match user permissions and watches for emerging threats. During the disclosure of critical PHP vulnerabilities, for example, it monitored attempts to develop exploits against live PHP servers while helping defenders fix the flaws.
Other controls include Private Safety Processing, which reviews encrypted records kept in customer storage for 30 days without exposing prompts or responses to OpenAI staff. API customers on Zero Data Retention generally must use it. Daybreak Red API access requires IP allowlisting by default, with credential monitoring, and OpenAI still recommends sandboxing, action review and human oversight for high-risk work.
Critical infrastructure gets special attention. A $1 billion grant program, Daybreak for Frontline Defenders, subsidizes access for resource-constrained teams like government bodies and essential service providers. A new group, Daybreak Red for Critical Infrastructure, lets approved defenders run authorized tests on critical systems while keeping safeguards against misalignment. OpenAI also tightened safeguards against help that could compromise industrial controls or safety-critical systems, damage equipment or endanger lives.
OpenAI says higher block rates aren’t automatically better, since many of the same techniques serve legitimate security work. Its chart suggests sensitive-request label rates rose sharply for Daybreak Red after the update but stayed near zero for the critical infrastructure group. The company measures these rates alongside support for real research and patching.
Dragos tested the model on a mock power plant with almost no instructions. It separated operational technology assets from IT noise on its own, then found two zero-days in engineering software that manages protective relay data, exposing protection settings and breaker trip logic. Dragos’s Rob T. Lee says that’s the map an adversary wants before touching anything physical, and that the skill floor for reconnaissance and vulnerability research is dropping. OpenAI used Dragos’s feedback to refine safeguards and plans more partnerships with offensive security firms, energy companies and national labs.
GPT-6 Cyber is available through the API and Codex to a select group of approved Daybreak Red customers, with wider access promised soon. GPT-5.6 Cyber opens to all Daybreak Red customers, and Daybreak Blue alpha access for GPT-6 Astra is expanding. Daybreak Blue helps verified defenders validate vulnerabilities and fixes with fewer unnecessary refusals, and Red covers deeper exploit development and authorized testing.
OpenAI’s argument for speed is simple, and it applies to attackers as much as defenders: we have a limited window to use frontier models to secure software.
“Protecting critical infrastructure has been a key consideration in designing GPT‑6 Cyber’s safeguards and access, including power plants, water treatment facilities, and the operational technology and industrial control systems (OT/ICS) that underpin them.” concludes the announcement.
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Pierluigi Paganini
(SecurityAffairs – hacking, OpenAI)
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