CVE-2026-93067

What the bug is

tc_aux_transfer() clamps an AUX read to the payload limit: size_t size = min_t(size_t, DP_AUX_MAX_PAYLOAD_BYTES - 1, msg->size); After the transfer it replaces size with the byte count the controller reports in AUX_BYTES: if (size) size = FIELD_GET(AUX_BYTES, auxstatus); AUX_BYTES is GENMASK(15, 8), so it can be up to 255. Nothing clamps it back to the request. tc_aux_read_data() reads that many bytes into the 16-byte auxrdata stack buffer, then copies them into the caller buffer. A reported count of 255 makes the read run to 256 bytes and overruns both. The controller should never report more than it was asked to transfer, so this is defense in depth rather than a live hole. The reported count is only lightly trusted, and the check is cheap. Clamp it back to the request, the same way ti-sn65dsi86 does in commit aca58eac52b8 ("drm/bridge: ti-sn65dsi86: Never store more than msg->size bytes in AUX xfer").

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/bridge/tc358767.c

What this is

DRM DRIVERS FOR BRIDGE CHIPSMAINTAINERS section matched on drivers/gpu/drm/bridge/ · Maintained

Kernel module

none to look for. The file would have gone into tc358767, and Debian does not compile it into that module, so finding tc358767 in lsmod would say nothing about this CVE.

Check it on the machine

grep -w CONFIG_DRM_TOSHIBA_TC358767 /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 5 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.

• bookworm, trixie, forky, sid, bookworm · linux-6.12n

n

not enabled on any flavour - this release does not build the code

Build switch

CONFIG_DRM_TOSHIBA_TC358767

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

2026-09-17 (31 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.18%, higher than 6.8% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

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
5.4	5.10.270	ebf00c51c9ac
5.4	5.15.221	424b762cc26d
5.4	6.1.188	dd6274706bec
5.4	6.6.157	982caa744fce
5.4	6.12.110	33c0b072e31d
5.4	6.18.52	57c567e0e8aa
5.4	7.2.6	9ff718df5473
5.4	7.3	ec6444a00c49

Debian advisories