# CVE-2026-68385: s390/checksum: Fix csum_partial() without vector facility

> A null pointer dereference in the s390 checksum implementation on systems without vector facilities can cause a kernel crash.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68385, DEBIAN-CVE-2026-68385, GHSA-p69g-gmqr-g4rm, UBUNTU-CVE-2026-68385

## What is CVE-2026-68385?

CVE-2026-68385 is a critical vulnerability in Linux, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

s390/checksum: Fix csum_partial() without vector facility

Currently csum_partial() calls csum_copy() with copy=false and dst=NULL.
On machines without the vector facility, csum_copy() falls back to
cksm(dst, ...), causing the checksum to be calculated from address zero
instead of the source buffer.

The VX implementation already checksums data loaded from src. Make the
fallback do the same by passing src to cksm().

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-68385?


## How do I fix CVE-2026-68385?

Apply the vendor's patch.

## Is CVE-2026-68385 being exploited?

There is no known exploitation of CVE-2026-68385 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68385 and fix it if it is affected.

What it is: CVE-2026-68385 is a critical vulnerability in Linux, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-68385 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-2026-68385/ (Markdown: https://insights.sbomify.com/CVE-2026-68385/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68385
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68385
- OSV: https://osv.dev/vulnerability/CVE-2026-68385

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68385/
Summaries are generated and may contain mistakes; the official description above is the record.