CVE-2026-93067

/// Technical 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:

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References