# CVE-2025-68773: spi: fsl-cpm: Check length parity before switching to 16 bit mode

> A buffer overrun in the Linux kernel fsl-cpm SPI driver allows local attackers to cause denial of service or potentially execute code via odd-sized transfers.

- **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:** 13 Jan 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-74414, BELL-CVE-2025-68773, DEBIAN-CVE-2025-68773, GHSA-wrfv-x882-24r3, ROOT-OS-DEBIAN-11-CVE-2025-68773, ROOT-OS-DEBIAN-12-CVE-2025-68773, ROOT-OS-DEBIAN-13-CVE-2025-68773, ROOT-OS-UBUNTU-2404-CVE-2025-68773, UBUNTU-CVE-2025-68773

## What is CVE-2025-68773?

CVE-2025-68773 is a memory corruption vulnerability in Linux, published on 13 Jan 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:

spi: fsl-cpm: Check length parity before switching to 16 bit mode

Commit fc96ec826bce ("spi: fsl-cpm: Use 16 bit mode for large transfers
with even size") failed to make sure that the size is really even
before switching to 16 bit mode. Until recently the problem went
unnoticed because kernfs uses a pre-allocated bounce buffer of size
PAGE_SIZE for reading EEPROM.

But commit 8ad6249c51d0 ("eeprom: at25: convert to spi-mem API")
introduced an additional dynamically allocated bounce buffer whose size
is exactly the size of the transfer, leading to a buffer overrun in
the fsl-cpm driver when that size is odd.

Add the missing length parity verification and remain in 8 bit mode
when the length is not even.

## Which versions are affected by CVE-2025-68773?


## How do I fix CVE-2025-68773?

Apply the vendor's patch.

## Is CVE-2025-68773 being exploited?

There is no known exploitation of CVE-2025-68773 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68773 and fix it if it is affected.

What it is: CVE-2025-68773 is a memory corruption vulnerability in Linux, published on 13 Jan 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-2025-68773 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-2025-68773/ (Markdown: https://insights.sbomify.com/CVE-2025-68773/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68773
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68773
- OSV: https://osv.dev/vulnerability/CVE-2025-68773

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68773/
Summaries are generated and may contain mistakes; the official description above is the record.