OpenAI discloses that GPT-5.6 Sol discovered a critical PHP vulnerability and releases a coordinated response framework

OpenAI says security firm Calif used GPT-5.6 Sol to discover a critical PHP vulnerability, Wiz independently reported two other related vulnerabilities, and the PHP development team released a fix on October 21 and urged users to upgrade. Based on this, OpenAI proposes a five-stage coordinated response framework for critical vulnerabilities covering vulnerability validation, phased information sharing, coordination with government agencies, broadening participation, and publishing remediation guidance, and calls the preparation period before public disclosure the "defender's window." OpenAI will also provide a PHP version check tool, plans to launch a companion Codex skill, and through the "Daybreak for Frontline Defenders" program will offer $1 billion in subsidized Daybreak service access credits.