# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 23 Aug 2026
- **Also known as:** BELL-CVE-2026-68279, DEBIAN-CVE-2026-68279, GHSA-p23r-m2g4-23pq, UBUNTU-CVE-2026-68279

## 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.

## Is CVE-2026-68279 being exploited?

There is no known exploitation of CVE-2026-68279 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68279 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-68279 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-68279/ (Markdown: https://insights.sbomify.com/CVE-2026-68279/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68279
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68279
- OSV: https://osv.dev/vulnerability/CVE-2026-68279

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68279/
Summaries are generated and may contain mistakes; the official description above is the record.