GPT-5.6 Sol turns a cyber-range record into Codex Security scans

A benchmark result enters the developer workflow

AI security tooling is moving from isolated challenge scores into tools that inspect working repositories. In a July 17 X post, OpenAI said GPT-5.6 Sol reached a new state of the art on “The Last Ones” cyber range and connected that result to Codex Security, its security-scanning plugin for Codex.

“GPT-5.6 Sol sets a new state of the art in cybersecurity on ‘The Last Ones’ cyber range. We’re already seeing that capability translate into defensive outcomes: helping teams find, validate, and fix vulnerabilities in real-world code.”

The material point is not just another model score. Cyber ranges test controlled offensive and defensive tasks, but OpenAI is positioning the same capability inside the developer loop: identify a vulnerability, check whether it is real, then produce a fix that can be reviewed in context. That makes the benchmark relevant to teams measuring mean time to remediation, review load, and false positives rather than only leaderboard rank.

The linked OpenAI setup guide describes two entry points. Desktop Codex users add the Codex Security plugin, open a prepared security-scan chat, select a project folder, and send the scan prompt. Codex CLI users can run the scan from a code directory. That design makes the plugin a repository-level workflow instead of a standalone scanner report.

OpenAI’s X account is normally used for product releases, model updates, and developer-facing workflow changes, so the pairing of GPT-5.6 Sol with Codex Security is a signal about commercialization as much as research. What to watch next is whether the plugin can show reproducible findings, patch quality, and regression coverage on large private codebases, where security teams care less about a single benchmark win and more about reviewable fixes that hold up under CI.