CVE-2026-68279 drm/dp/mst: fix OOB reads in remote DPCD/I2C sideband reply parsers
A malicious MST hub can trigger out-of-bounds reads in the Linux kernel, potentially leaking memory or causing a crash.
- 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-2026-68279?
CVE-2026-68279 is a memory corruption vulnerability in Linux, published on 10 Aug 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/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]
Which versions are affected by CVE-2026-68279?
How do I fix CVE-2026-68279?
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-2026-68279 being exploited?
There is no known exploitation of CVE-2026-68279 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68279, DEBIAN-CVE-2026-68279, GHSA-p23r-m2g4-23pq, UBUNTU-CVE-2026-68279.