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CVE-2026-74313
vduse: hold vduse_lock across IDR lookup in open path
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/vdpa. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-74313 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 | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
vduse_dev_open() looks up struct vduse_dev through the IDR and then acquires dev->lock only after vduse_lock has been dropped. This leaves a window where a concurrent VDUSE_DESTROY_DEV can remove the same object from the IDR and free it before the open path locks the device, leading to a use-after-free. Close this race by keeping vduse_lock held until dev->lock has been acquired in the open path, matching the lock ordering already used by the destroy path.
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.
drivers/vdpa/vdpa_user/vduse_dev.c
- What this is
- VIRTIO COREMAINTAINERS section matched on drivers/vdpa/ · virtualization@lists.linux.dev · Maintained
- Kernel module
- vduse
Check it on the machine
grep -wE 'CONFIG_VDPA|CONFIG_VDPA_USER' /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 vdusePrints 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 does not build this code in 1 release. It does build it in 3 releases, so the answer depends on which release the machine runs.
- bookwormn
- trixieMnot built on riscv64/riscv64
- forky, sidm
- n
- not enabled on any flavour - this release does not build the code
- M
- a module where it is built at all; some flavours do not build it
- m
- a loadable module on every flavour - check lsmod, can be blacklisted
- Build switches
- CONFIG_VDPA, CONFIG_VDPA_USER
- 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
- 2026-08-15 (2 months ago)source
- CVSS
- 8.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.0% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/vdpa
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.15 | 5.15.212 | 35483c5306e0 |
| 5.15 | 6.1.178 | 5c1560be8aa6 |
| 5.15 | 6.6.145 | 93ed4692f229 |
| 5.15 | 6.12.97 | d94e2947203a |
| 5.15 | 6.18.40 | a2d0a57538fd |
| 5.15 | 7.1.5 | 79e12c891940 |
| 5.15 | 7.2 | e440e0777489 |
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 vulnerability is only reachable via local syscalls on VDUSE character devices: open(2) on /dev/vduse/$NAME racing with ioctl(VDUSE_DESTROY_DEV) on /dev/vduse/control. It is not triggered by remote network traffic, adjacent wireless protocols, or physical device attachment.
- AC:LAttack complexity, low
- The attacker fully controls both sides of the race by creating a VDUSE device, then concurrently calling open() and VDUSE_DESTROY_DEV from their own threads. No timing or layout conditions outside attacker control are required beyond standard thread scheduling.
- PR:LPrivileges required, low
- Neither the open nor destroy paths enforce capabilities beyond device-node access; only VIRTIO_ID_NET creation requires CAP_NET_ADMIN. VDUSE is designed so userspace dataplane operators with access to /dev/vduse nodes can create, open, and destroy block devices without full host admin rights.
- UI:NUser interaction, none
- Exploitation requires no victim interaction. The attacker creates their own VDUSE instance and triggers the open/destroy race from their process; no separate user must mount, configure, or open the device.
- S:CScope, changed
- On cloud and virtualization hosts where VDUSE is delegated to containers or NFV tenant workloads, kernel UAF exploitation crosses from the tenant/container security boundary to full host kernel compromise, comparable to a VM or sandbox escape.
- C:HConfidentiality impact, high
- The race produces a use-after-free of kmalloc'd struct vduse_dev. Locking and dereferencing the freed object, plus subsequent ioctl/read/write using dangling file->private_data, enables slab reuse and arbitrary kernel memory disclosure.
- I:HIntegrity impact, high
- UAF of vduse_dev allows heap grooming over mutexes, virtqueue pointers, and config buffers. Follow-on VDUSE ioctls (SET_CONFIG, VQ_SETUP, IOTLB) on the dangling fd provide exploitable arbitrary-write and control-flow hijack primitives.
- A:HAvailability impact, high
- Use-after-free during mutex_lock on the freed device or later VDUSE operations can immediately corrupt kernel memory and trigger oops/panic, fully denying system availability even before full exploitation.