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CVE-2026-80700
drm/vmwgfx: validate external BO copy bounds for both stride paths
Published 2026-08-28 (2 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-2026-80700 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 | 6.12.105-1 | Update the kernel and reboot. Fixed in 6.12.105-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. 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
vmw_external_bo_copy() trusts caller-supplied offsets, strides, and heights and operates on imported dma-buf vmaps: - The equal-stride memcpy() bound was clamped after subtracting the offsets from dst_size and src_size; an offset larger than the BO size wraps the unsigned subtraction to a huge value and the resulting memcpy() runs off the end of the vmap. dst_stride * height is also a u32 multiplication that can overflow. - The non-equal-stride row-by-row path had no bound at all. The loop touches bytes through offset + (height - 1) * stride + width_in_bytes, with only a WARN_ON(dst_stride < width_in_bytes), and could likewise step past the end of either mapping. The offsets and strides are derived from STDU/SOU plane state, so a configured CRTC submitting a crafted atomic commit on an imported framebuffer can reach this path. Validate the exact row-copy endpoint against each BO's size up front using check_mul_overflow() and check_add_overflow(). Use the bulk memcpy() path only when width_in_bytes covers the whole stride; otherwise copy one row at a time so partial-row updates near the bottom of a framebuffer remain valid. Also reject zero strides and stride < width_in_bytes, both of which the row-by-row path cannot represent safely.
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/vmwgfx/vmwgfx_blit.c
- What this is
- DRM DRIVER FOR VMWARE VIRTUAL GPUMAINTAINERS section matched on drivers/gpu/drm/vmwgfx/ · dri-devel@lists.freedesktop.org · Supported
- Kernel module
- vmwgfx
Check it on the machine
grep -w CONFIG_DRM_VMWGFX /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 vmwgfxPrints 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, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le
- trixieMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/cloud-arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- M
- a module where it is built at all; some flavours do not build it
- Build switch
- CONFIG_DRM_VMWGFX
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
- 2026-08-28 (2 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 2.3% 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 |
|---|---|---|
| 6.6.49 | 6.6.151 | 4e0f669e2951 |
| 6.11 | 6.12.103 | e7b25a601178 |
| 6.11 | 6.18.44 | 042ca3877955 |
| 6.11 | 7.1.8 | 5e4a2d15637a |
| 6.11 | 7.2 | 706c93c5813c |
| 6.10.8 | 0 | 0 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4788-1 | 2026-09-19 | bookworm 6.12.107-1~deb12u1 | 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 flaw is reached only via local DRM KMS ioctls on /dev/dri/card0: DRM_IOCTL_MODE_ATOMIC drives STDU/SOU plane updates that call vmw_bo_cpu_blit() -> vmw_external_bo_copy(); vmwgfx is not exposed through any network, adjacent-radio, or physical-bus interface.
- AC:LAttack complexity, low
- An attacker with DRM master fully controls atomic plane state, damage clips, pitches, and prime-imported framebuffer geometry that derive dst/src offsets, strides, and height; crafted values reliably trigger unsigned wrap or unbounded row copies without races or victim-dependent layout.
- PR:LPrivileges required, low
- DRM_IOCTL_MODE_ATOMIC is gated by DRM_MASTER, not real root; on VMware guests and VDI desktops the logged-in session user holding master (typical video/render group access) can prime-import a dma-buf, configure a CRTC, and submit the malicious atomic commit.
- UI:NUser interaction, none
- Exploitation requires only the attacker opening the DRM device and issuing crafted atomic commits with an imported framebuffer; no actions by another user such as mounting filesystems or opening files are needed.
- S:UScope, unchanged
- Out-of-bounds memcpy corrupts adjacent guest-kernel memory around imported dma-buf vmaps and internal display BO mappings, enabling guest-kernel privilege escalation; impact stays within the guest kernel security domain and does not directly cross a VM/host or IOMMU boundary.
- C:HConfidentiality impact, high
- The bug performs unchecked memcpy from attacker-influenced source mappings past buffer ends (equal-stride unsigned underflow and unbounded row-by-row copies), yielding an out-of-bounds kernel read primitive that can disclose adjacent heap/vmalloc data including kernel pointers.
- I:HIntegrity impact, high
- The same unchecked copies write past the end of destination vmaps, providing an out-of-bounds kernel write primitive that can corrupt adjacent objects and be developed into arbitrary memory modification or code execution.
- A:HAvailability impact, high
- Large out-of-bounds memcpy operations can immediately corrupt critical kernel structures or touch unmapped pages, causing kernel oops/panic; the atomic-commit trigger can be repeated to deny availability after reboot.