CVE-2026-6426

Name	CVE-2026-6426
Description	A type mismatch vulnerability was found in QEMU's vhost inflight migration VMState handling. The destination buffer size is stored as a uint64_t but read by the VMS_VBUFFER load path as a signed int32_t. On little-endian hosts, a crafted incoming migration state with bit 31 set causes the value to be interpreted as negative and then implicitly converted to a very large size_t, leading qemu_get_buffer() to copy migration-stream data beyond the bounds of the mmap-backed inflight region. This can result in a crash of the QEMU process or memory corruption. Exploitation requires control of the migration producer or write access to the migration channel, combined with a destination configured to use vhost inflight migration.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
qemu (PTS)	bullseye	1:5.2+dfsg-11+deb11u3	vulnerable
	bullseye (security)	1:5.2+dfsg-11+deb11u5	vulnerable
	bookworm	1:7.2+dfsg-7+deb12u18	vulnerable
	bookworm (security)	1:7.2+dfsg-7+deb12u15	vulnerable
	trixie	1:10.0.11+ds-0+deb13u1	vulnerable
	trixie (security)	1:10.0.2+ds-2+deb13u1	vulnerable
	forky, sid	1:11.0.3+ds-2	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
qemu	source	(unstable)	(unfixed)

https://bugzilla.redhat.com/show_bug.cgi?id=2513498
https://gitlab.com/qemu-project/qemu/-/work_items/3675