Linux KVM guest-host escape rated critical, may represent a new way to attack penguin-powered networking
Party like it’s CVE-2026-99999 – a 9.3-rated nasty called PwnEscape
A critical vulnerability, dubbed PwnEscape, has been discovered in Linux KVM, a hypervisor widely used in most hyperscale clouds. The flaw, named by researcher Paulos Yibelo, could allow a guest-host escape, representing a new way to attack Linux systems. The issue is rated critical, as it enables guests to access the host server by sending malformed IPv4 packets.
This threat arises due to Linux's optimization of network packet checksum operations, which allows less-trusted guest-controlled metadata to influence validation stages. The security breach could potentially lead to arbitrary code execution on the host, a Denial of Service, or information disclosure of sensitive memory. While major cloud providers like AWS and Google Cloud claim to be unaffected, the discovery highlights a new class of threats to Linux networking, demanding urgent attention from developers and users alike.
Written by urgent.news from The Register's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
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