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CVE-2026-43248
vhost: move vdpa group bound check to vhost_vdpa
Published 2026-05-06 (5 months ago) by the Linux kernel CNA. Subsystem drivers/vdpa. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-43248 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 | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixed | 6.12.85-1 | Update the kernel and reboot. Fixed in 6.12.85-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 6.19.6-1 | Update the kernel and reboot. Fixed in 6.19.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 6.19.6-1 | Update the kernel and reboot. Fixed in 6.19.6-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Remove duplication by consolidating these here. This reduces the posibility of a parent driver missing them. While we're at it, fix a bug in vdpa_sim where a valid ASID can be assigned to a group equal to ngroups, causing an out of bound write.
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/mlx5/net/mlx5_vnet.c
drivers/vdpa/vdpa_sim/vdpa_sim.c
drivers/vhost/vdpa.c
- What this is
- MELLANOX MLX5 VDPA DRIVERMAINTAINERS section matched on drivers/vdpa/mlx5/ · virtualization@lists.linux.dev · Supported
- Kernel module
- none to look for. The file would have gone into vdpa_sim, and Debian does not compile it into that module, so finding vdpa_sim in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_VDPA|CONFIG_VDPA_SIM' /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.
Show whether Debian builds this, per release
Debian does not build this code. In 4 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sidn
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_VDPA, CONFIG_VDPA_SIM
- 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
- 2026-05-06 (5 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.2% 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 |
|---|---|---|
| 5.19 | 6.12.75 | ddb57354634b |
| 5.19 | 6.18.16 | 7441d35d14d9 |
| 5.19 | 6.19.6 | 406db68f9cb9 |
| 5.19 | 7.0 | cd025c1e876b |
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 vulnerable path is reached through local `ioctl()` calls on a `/dev/vhost-vdpa-*` character device, not by network or adjacent traffic.
- AC:LAttack complexity, low
- The attacker controls the ioctl arguments, including the group index and ASID, and no race or external timing condition is required once the device is accessible.
- PR:LPrivileges required, low
- Creating or binding vDPA devices is administrative, but a delegated/local VM or vDPA process with access to the vhost-vdpa device can trigger the ioctl without further kernel capability checks. Choosing the higher severity option, this is Low rather than High.
- UI:NUser interaction, none
- No victim user action is needed; the local attacker directly opens the device, becomes vhost owner, and issues the ioctl.
- S:UScope, unchanged
- The impact is corruption of host kernel memory from a local host device interface, which is a standard kernel privilege/security-domain impact rather than a VM escape or separate authority crossing.
- C:HConfidentiality impact, high
- The missing group bound permits out-of-bounds kernel heap access in the parent set_group_asid path, and such memory corruption can reasonably be developed into kernel memory disclosure.
- I:HIntegrity impact, high
- The bug permits an out-of-bounds kernel write of ASID/group state or adjacent locking/state fields, making kernel memory corruption and potential control-flow or privilege manipulation plausible.
- A:HAvailability impact, high
- Even without full exploitation, the out-of-bounds write can corrupt kernel heap state and can reasonably crash or panic the kernel.