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CVE-2026-64051
accel/qaic: Add overflow check to remap_pfn_range during mmap
Published 2026-07-19 (3 months ago) by the Linux kernel CNA. Subsystem drivers/accel. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-64051 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 | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | fixed | 6.12.94-1 | Update the kernel and reboot. Fixed in 6.12.94-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.12-1 | Update the kernel and reboot. Fixed in 7.0.12-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The call to remap_pfn_range in qaic_gem_object_mmap is susceptible to (re)mapping beyond the VMA if the BO is too large. This can cause use after free issues when munmap() unmaps only the VMA region and not the additional mappings. To prevent this, check the remaining size of the VMA before remapping and truncate the remapped length if sg->length is too large. [jhugo: fix braces from checkpatch --strict]
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/accel/qaic/qaic_data.c
- What this is
- QUALCOMM CLOUD AI (QAIC) DRIVERMAINTAINERS section matched on drivers/accel/qaic/ · linux-arm-msm@vger.kernel.org · Supported
Check it on the machine
grep -wE 'CONFIG_DRM_ACCEL|CONFIG_DRM_ACCEL_QAIC' /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 3 releases. The build rule could not be established for 1 release, so nothing is claimed about those.
- bookworm?
- trixie, forky, sidn
- ?
- not established - no Makefile entry for the affected file
- n
- not enabled on any flavour - this release does not build the code
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
- Build switches
- CONFIG_DRM_ACCEL, CONFIG_DRM_ACCEL_QAIC
- 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
- 2026-07-19 (3 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
- unimportantsource
- Subsystem
- drivers/accel
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.4 | 6.6.142 | 9baafc2fea09 |
| 6.4 | 6.12.92 | 8dd6edbe2677 |
| 6.4 | 6.18.34 | 97a8e89cdef3 |
| 6.4 | 7.0.11 | 8c795012d0e0 |
| 6.4 | 7.1 | aa16b2bc0f02 |
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
- Exploitation requires local access via the QAIC accel device node (/dev/accel/accel*) through DRM ioctls and mmap syscalls; there is no network-facing attack surface.
- AC:LAttack complexity, low
- An attacker fully controls BO allocation size, partial mmap length, and munmap timing, deterministically mapping PFNs beyond the VMA without races or external conditions.
- PR:LPrivileges required, low
- No DRM master or root is required; any unprivileged local user with access to the accel device node (common on shared cloud AI inference hosts) can create a BO, partial-mmap it, and trigger the bug.
- UI:NUser interaction, none
- Exploitation requires only attacker-initiated ioctl and mmap operations on an open accel file descriptor, with no victim interaction.
- S:UScope, unchanged
- The UAF corrupts kernel page-table mappings within the same kernel security domain; it does not cross VM, container, or IOMMU boundaries.
- C:HConfidentiality impact, high
- The commit explicitly identifies a use-after-free of page structures left mapped past the VMA; UAF of kernel mappings enables arbitrary kernel memory read primitives.
- I:HIntegrity impact, high
- UAF on kernel page structures can be leveraged for arbitrary kernel memory writes and local privilege escalation through heap grooming and control of freed pages.
- A:HAvailability impact, high
- Accessing stale PFN mappings after BO teardown causes kernel oops/panic; UAF reliably threatens system availability even before full exploitation.