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CVE-2026-63881
drm/amdkfd: fix a vulnerability of integer overflow in kfd debugger
Published 2026-07-19 (3 months ago) by the Linux kernel CNA. Subsystem drivers/gpu. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-63881 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
get_queue_ids() computes array_size = num_queues * sizeof(uint32_t), which could overflow on 32-bit size_t build. using array_size() instead, it saturates to SIZE_MAX on overflow. (cherry picked from commit 2d57a0475f085c08b49312dfd8edcb461845f285)
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/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
- What this is
- AMD KFDMAINTAINERS section matched on drivers/gpu/drm/amd/amdkfd/ · amd-gfx@lists.freedesktop.org · Supported
Show whether Debian builds this, per release
Not established. This site could not find the build rule for the affected file in the kernel trees Debian ships, so it has no answer about whether Debian compiles this code. Read that as unknown, never as absent.
- bookworm, trixie, forky, sid?
- ?
- not established - no Makefile entry for the affected file
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.
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
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
- 0.19%, higher than 8.0% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- drivers/gpu
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.5 | 6.6.143 | 4e5f808b4541 |
| 6.5 | 6.12.93 | de70a8099239 |
| 6.5 | 6.18.35 | 5cf4a41aa0d7 |
| 6.5 | 7.0.12 | 4f9eeedc3d31 |
| 6.5 | 7.1 | 93f5534b35a0 |
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 a local `ioctl()` on `/dev/kfd` via `AMDKFD_IOC_DBG_TRAP` with `KFD_IOC_DBG_TRAP_SUSPEND_QUEUES` or `KFD_IOC_DBG_TRAP_RESUME_QUEUES`; there is no network, adjacent-radio, or physical-access path to the vulnerable code.
- AC:LAttack complexity, low
- On affected 32-bit `size_t` kernel builds, an attacker fully controls `num_queues` in the ioctl and can reliably force the multiply overflow (e.g. `num_queues >= 0x40000001`) to trigger undersized `memdup_user()` followed by unbounded kernel heap corruption.
- PR:LPrivileges required, low
- A local unprivileged user with AMDGPU/KFD device access can open `/dev/kfd`, enable the debug runtime and debug trap on their own process (no ptrace or root required), then invoke suspend/resume with a malicious `num_queues` value.
- UI:NUser interaction, none
- Exploitation is achieved entirely through attacker-initiated ioctl calls in an established KFD debug session; no victim interaction is required.
- S:UScope, unchanged
- Impact is kernel heap corruption and potential local privilege escalation within the same kernel security boundary, not a cross-boundary escape such as VM guest-to-host or IOMMU bypass.
- C:HConfidentiality impact, high
- The integer overflow causes a heap buffer far smaller than `num_queues`, and subsequent `q_array_get_index()`/`copy_to_user()` operations perform out-of-bounds kernel reads that can disclose adjacent heap memory and be leveraged for arbitrary read primitives.
- I:HIntegrity impact, high
- `q_array_invalidate()` and per-queue status updates write attacker-influenced values (`KFD_DBG_QUEUE_INVALID_MASK`/`KFD_DBG_QUEUE_ERROR_MASK`) far beyond the allocated buffer, constituting an out-of-bounds heap write exploitable for control-flow hijacking and arbitrary kernel modification.
- A:HAvailability impact, high
- Writing billions of 32-bit values past a 4-byte kmalloc object corrupts adjacent kernel heap metadata and objects, readily causing kernel oops/panic and complete loss of availability even before full exploitation.