CVE-2026-68279

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

drm/dp/mst: fix OOB reads in remote DPCD/I2C sideband reply parsers

drm_dp_sideband_parse_remote_dpcd_read() reads num_bytes from the raw

message and then unconditionally does:

memcpy(bytes, &raw->msg[idx], num_bytes);

without checking that idx + num_bytes <= raw->curlen. raw->msg[] is

256 bytes; if a malicious or misbehaving MST hub sets num_bytes larger

than the remaining payload, the memcpy reads past the received data

into whatever follows in raw->msg[].

drm_dp_sideband_parse_remote_i2c_read_ack() has the same flaw (noted

with a /* TODO check */ comment since the code was introduced).

Fix both functions by using a single combined check

(idx + num_bytes > curlen) before each memcpy. Since num_bytes is u8,

it is always >= 0, so this strictly subsumes the simpler idx > curlen

form and no separate step is needed.

[added missing fixes tag]

/// 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