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CVE-2026-72358
drm/xe/pt: prevent invalid cursor access for purged BOs
Published 2026-08-15 (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-2026-72358 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 | not affected | 6.12.113-1 | Nothing to do. trixie never shipped the vulnerable code. |
| 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
During a page table walk for binding, xe_pt_stage_bind() explicitly skips initializing the xe_res_cursor for purged BOs, treating them similarly to NULL VMAs by only setting the cursor size. However, xe_pt_hugepte_possible() and xe_pt_scan_64K() did not check if the BO was purged before attempting to walk the cursor using xe_res_dma() and xe_res_next(). Because the cursor was left uninitialized for purged BOs, this falls through and triggers warnings like: WARNING: drivers/gpu/drm/xe/xe_res_cursor.h:274 at xe_res_next Fix this by explicitly checking if the BO is purged in both xe_pt_hugepte_possible() and xe_pt_scan_64K(), returning early just as we do for NULL VMAs, avoiding the invalid cursor accesses entirely. As a precaution, also zero-initialize the cursor in xe_pt_stage_bind() to ensure we don't pass garbage data into the page table walkers if we ever hit a similar edge case in the future. (cherry picked from commit 4c7b9c6ece32440e5a435a92076d049450cd2d2e)
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/xe/xe_pt.c
- What this is
- INTEL DRM XE DRIVER (Lunar Lake and newer)MAINTAINERS section matched on drivers/gpu/drm/xe/ · intel-xe@lists.freedesktop.org · Supported
- Kernel module
- xe
Check it on the machine
grep -w CONFIG_DRM_XE /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 xePrints 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. The build rule could not be established for 1 release, so nothing is claimed about those.
- bookworm?
- trixieMnot built on amd64/cloud-amd64, arm64/arm64-16k, arm64/cloud-arm64, armel/rpi, ppc64el/powerpc64le-64k, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/arm64-16k, arm64/cloud-arm64, loong64/loong64, ppc64el/powerpc64le-64k, s390x/s390x
- ?
- not established - no Makefile entry for the affected file
- M
- a module where it is built at all; some flavours do not build it
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 switch
- CONFIG_DRM_XE
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
- 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
- 0.17%, higher than 5.4% 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 |
|---|---|---|
| 7.1 | 7.1.5 | 2b6b3f98d0e9 |
| 7.1 | 7.2 | 8a0fb57675be |
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 ioctl access to the Intel Xe DRM render node (/dev/dri/renderD*) via XE_VM_BIND and XE_MADVISE to drive purged-buffer page-table rebinds through xe_pt_stage_bind(); this path is not reachable over the network or without local GPU device access.
- AC:LAttack complexity, low
- An attacker controls the full trigger sequence—marking BOs DONTNEED via madvise, inducing memory pressure to purge backing store, and forcing rebind—so the uninitialized-cursor walk is reliably reachable without races or conditions outside attacker influence.
- PR:LPrivileges required, low
- Only standard unprivileged local access to the DRM render node is required (typical render/video group membership on desktops, cloud GPU instances, and shared workstations); no real root/CAP_SYS_ADMIN and user namespaces do not grant additional reach.
- UI:NUser interaction, none
- No victim or administrator interaction is needed; the attacker drives the entire sequence through their own DRM ioctls and deliberate memory-pressure to purge and rebind their own mapped buffer objects.
- S:UScope, unchanged
- Impact is kernel memory corruption and denial-of-service within the same OS security boundary (potential local privilege escalation), not a VM escape, IOMMU/DMA boundary bypass, or cross-tenant isolation break.
- C:HConfidentiality impact, high
- xe_pt_hugepte_possible() and xe_pt_scan_64K() read uninitialized xe_res_cursor stack fields via xe_res_dma()/xe_res_next() on purged BOs, constituting kernel memory corruption that can leak adjacent stack/heap data or skew page-table decisions.
- I:HIntegrity impact, high
- Garbage cursor mem_type/node pointers drive buddy-allocator list traversal during page-table walks, enabling kernel heap metadata corruption and potential arbitrary write or control-flow hijack primitives beyond the intended safe NULL/scratch PTE rebind path.
- A:HAvailability impact, high
- Invalid cursor traversal triggers XE_WARN_ON in xe_res_next and can dereference corrupt buddy-list pointers during purged-BO rebind, causing kernel warnings, oops, or panic and denying GPU and system availability.