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CVE-2026-80741
drm/log: Fix out-of-bounds read on empty message length
Published 2026-09-03 (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-2026-80741 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 | 7.1.10-1 | Update the kernel and reboot. Fixed in 7.1.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.10-1 | Update the kernel and reboot. Fixed in 7.1.10-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
drm_log_draw_kmsg_record() accesses s[len - 1] to strip the trailing newline, but len is unsigned int. If len is 0, the subtraction wraps to UINT_MAX, causing an out-of-bounds read. Add an early return when len is 0.
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/clients/drm_log.c
- What this is
- DRM LOGMAINTAINERS section matched on drivers/gpu/drm/clients/drm_log.c · dri-devel@lists.freedesktop.org · Supported
Check it on the machine
grep -wE 'CONFIG_DRM_CLIENT_LIB|CONFIG_DRM_CLIENT_LOG' /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 2 releases. The build rule could not be established for 2 releases, 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_CLIENT_LIB, CONFIG_DRM_CLIENT_LOG
- 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
- 2026-09-03 (2 months ago)source
- CVSS
- 7.1 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.16%, higher than 5.3% 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 |
|---|---|---|
| 6.14 | 6.18.46 | 16a2716910ec |
| 6.14 | 7.1.10 | 16bcea56f420 |
| 6.14 | 7.2 | 60baa179ed13 |
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 bug is in drm_log, an in-kernel DRM boot console that renders printk records to the framebuffer; it is only reached from the local printk/nbcon console path, not from any network protocol or physical bus.
- AC:LAttack complexity, low
- Once CONFIG_DRM_CLIENT_LOG is active (common on embedded/kiosk displays), a local actor can drive printk/console output; if a zero-length record is delivered to drm_log_draw_kmsg_record(), the unsigned wrap to UINT_MAX makes the OOB read deterministic rather than race-dependent.
- PR:LPrivileges required, low
- No root or DRM master is required to reach the console printk path; unprivileged local processes routinely trigger kernel logging via syscalls and /dev/kmsg (CAP_SYSLOG is obtainable in user namespaces), and drm_log only refuses to draw when a userspace DRM master is already held.
- UI:NUser interaction, none
- Exploitation does not require any victim to click, mount, or open a file; it is triggered automatically when the kernel console layer emits a qualifying (including zero-length) message to the drm_log nbcon handler.
- S:UScope, unchanged
- Impact stays within kernel context on the same machine (display logger crash/OOB read); it does not cross a VM, container, or IOMMU security boundary.
- C:HConfidentiality impact, high
- With len=0, s[len-1] indexes s[UINT_MAX-1], an unbounded out-of-bounds kernel read; per kernel CVSS guidance, OOB reads are rated High even when the immediate fault dominates.
- I:NIntegrity impact, none
- The defect is a read-side integer underflow only; it does not corrupt or write adjacent memory and provides no direct arbitrary-write or code-execution primitive.
- A:HAvailability impact, high
- Reading at offset UINT_MAX from the printk outbuf is virtually certain to fault the console thread with a kernel oops/panic, denying display and potentially halting the system on embedded drm_log deployments.