Security1 hOctober 20, 2026, 16:37

CVE-2026-99999 PwnEscape: one checksum breaks VM isolation

PWNAI researcher Paulos Yibelo found CVE-2026-99999 (PwnEscape) in the Linux networking stack, rated 9.3 by cve.org. A flaw in IPv4 checksum offload handling lets a guest VM escape to the host over virtio-net. Fix 6785011f8b16 landed in mainline on October 14, 2026, with distros backporting separately.

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CVE-2026-99999 PwnEscape: one checksum breaks VM isolation

CVSS 9.3 on cve.org; Red Hat scores it 8.8
Flaw is in the order of IPv4 checksum validation and write
Fix 6785011f8b16 merged to mainline on October 14, 2026
Found during Vercel's $1 million Sandbox challenge

#Linux#Vercel

PwnEscape: guest-to-host KVM escape via Linux checksum processing (CVE-2026-99999)

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CVE-2026-99999 PwnEscape: one checksum breaks VM isolation

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Meta Muse: a personal AI agent with an isolated Linux VM and Sentinel guard agent

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