Researchers rediscover Vercel KVM escape in 2 hours using AI agent and an unredacted screenshot clue
evilsocket · x · 2026-10-16
PWN.AI researcher Paulos Yibelo disclosed a guest-to-host KVM escape (CVE-2026-99999) in Vercel's Sandbox, earning a $50,000 bounty under Vercel's $1 million sandbox-break challenge. The bug lies in guest-controlled checksum metadata in Linux networking that rewrites an IPv4 header after kernel validation, enabling host-memory disclosure and a full escape.
The twist: @0x4D31 independently rediscovered it in 2 hours. He let OpenAI's gpt-5.6-cyber (daybreak red) explore a devbox for 1.5 hours, then spotted that the word after "guest-controlled" in the bounty screenshot wasn't fully redacted — three dots leaked "virtio". Passing that hint to his agent, it found and validated the vulnerability in 30 minutes. A lesson in both AI-assisted vuln research and redaction opsec.
Related event: PwnEscape: KVM Guest-to-Host Escape Bug Detailed(3 posts)→
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