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CVE-2026-74614
vsock/virtio: read virtqueues under worker locks
Published 2026-08-22 (2 months ago) by the Linux kernel CNA. Subsystem net/vmw_vsock. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-74614 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6466-1 · 2026-08-25 · text | 6.12.105-1 | Update the kernel and reboot. DSA-6466-1 shipped the fix on 2026-08-25, in 6.12.105-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.9-1 | Update the kernel and reboot. Fixed in 7.1.9-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.9-1 | Update the kernel and reboot. Fixed in 7.1.9-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4788-1 · 2026-09-19 · text | 6.12.107-1~deb12u1 | Update the kernel and reboot. DLA-4788-1 shipped the fix on 2026-09-19, in 6.12.107-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Commit bd50c5dc182b ("vsock/virtio: add support for device suspend/resume") made the *_run flags transition from false to true when restore installs replacement virtqueues. The RX, TX and event workers read their virtqueue before locking and checking the corresponding flag, so a worker delayed across freeze and restore can observe the replacement queue's running state while retaining a pointer to the deleted queue. Read each virtqueue under its mutex after checking the run flag, keeping the pointer and state in the same queue generation.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
net/vmw_vsock/virtio_transport.c
- What this is
- VIRTIO AND VHOST VSOCK DRIVERMAINTAINERS section matched on net/vmw_vsock/virtio_transport.c · kvm@vger.kernel.org · Maintained
- Kernel module
- vmw_vsock_virtio_transport
Check it on the machine
grep -wE 'CONFIG_VIRTIO_VSOCKETS|CONFIG_VSOCKETS' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w vmw_vsock_virtio_transportPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.
- bookworm, trixie, forky, sid, bookworm · linux-6.12m
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switches
- CONFIG_VIRTIO_VSOCKETS, CONFIG_VSOCKETS
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-22 (2 months ago)source
- CVSS
- 8.4 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.14%, higher than 3.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/vmw_vsock
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.15.138 | 5.15.216 | 941329ce14c5 |
| 5.19 | 6.1.183 | 29dd10583bf9 |
| 5.19 | 6.6.152 | a1fb0c5b8a7c |
| 5.19 | 6.12.104 | eae099c764c7 |
| 5.19 | 6.18.45 | bd43a7ec668b |
| 5.19 | 7.1.9 | 1cecb4202afd |
| 5.19 | 7.2 | ebac8f6b1ef0 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4788-1 | 2026-09-19 | bookworm 6.12.107-1~deb12u1 | tracker |
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DSA-6466-1 | 2026-08-25 | trixie 6.12.105-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The bug is in the guest virtio-vsock driver reached via AF_VSOCK sockets and virtio virtqueue completions, not via routable network protocols; per kernel CNA guidance vsock and virtio guest-driver bugs are scored Local even when the hypervisor is the peer.
- AC:LAttack complexity, low
- An attacker or malicious host controls both sides of the race by flooding vsock/virtqueue traffic to queue RX/TX/event workers while virtio_vsock_freeze/restore deletes and replaces virtqueues, making the stale pre-lock virtqueue pointer race reliable and repeatable.
- PR:NPrivileges required, none
- No guest privileges are required in the highest-impact scenario: a malicious hypervisor or host-initiated suspend/migrate triggers freeze/restore while virtio completions queue workers, matching confidential-computing models where the host is untrusted and holds no guest credentials.
- UI:NUser interaction, none
- Vulnerable RX/TX/event workers run automatically from virtqueue IRQ callbacks on a dedicated workqueue; no victim must mount filesystems, open files, or take deliberate action beyond normal virtio-vsock device operation and VM lifecycle events.
- S:UScope, unchanged
- Corruption is confined to the guest kernel virtio-vsock driver; exploited impact stays within the guest security boundary and does not cross to the hypervisor (guest-to-host escape would involve vhost-vsock on the host, not this guest-side driver).
- C:HConfidentiality impact, high
- Use-after-free of a deleted virtqueue: virtqueue_disable_cb, virtqueue_get_buf, and virtqueue_enable_cb dereference freed vring_virtqueue slab memory, enabling attacker-controlled reuse and arbitrary kernel memory disclosure typical of virtio UAF bugs.
- I:HIntegrity impact, high
- Corrupted virtqueue metadata permits out-of-bounds ring/index manipulation and further virtqueue operations, furnishing heap corruption and arbitrary-write primitives suitable for guest ring-0 code execution and privilege escalation.
- A:HAvailability impact, high
- Operating on freed virtqueues triggers KASAN slab-use-after-free and kernel BUG/oops/panic (as in the related virtio-vsock freeze bug CVE-2026-74613), fully denying guest availability even when full exploitation is not attempted.