CVE-2026-93067 drm/bridge: tc358767: clamp the reported AUX read size to the request
A buffer overflow in the Linux kernel tc358767 DRM bridge driver allows local attackers to execute code or cause a denial of service via crafted AUX transfers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93067?
CVE-2026-93067 is a memory corruption vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
drm/bridge: tc358767: clamp the reported AUX read size to the request
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").
Which versions are affected by CVE-2026-93067?
How do I fix CVE-2026-93067?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-93067 being exploited?
There is no known exploitation of CVE-2026-93067 in the wild and no public exploit code.
Sources
Also known as AZL-102731, BELL-CVE-2026-93067, DEBIAN-CVE-2026-93067, GHSA-wpcc-v879-hj4w, UBUNTU-CVE-2026-93067.