# CVE-2026-45994: ibmasm: fix OOB reads in command_file_write due to missing size checks

> An attacker can trigger out-of-bounds reads in the ibmasm driver to leak kernel heap memory to the service processor.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 May 2026
- **Updated:** 14 Jun 2026
- **Also known as:** AZL-88458, BELL-CVE-2026-45994, DEBIAN-CVE-2026-45994, GHSA-rcq2-mghh-wcf4, ROOT-OS-DEBIAN-11-CVE-2026-45994, ROOT-OS-DEBIAN-12-CVE-2026-45994, ROOT-OS-UBUNTU-2204-CVE-2026-45994, ROOT-OS-UBUNTU-2404-CVE-2026-45994, UBUNTU-CVE-2026-45994

## What is CVE-2026-45994?

CVE-2026-45994 is a high-severity vulnerability in Linux kernel, published on 27 May 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:

ibmasm: fix OOB reads in command_file_write due to missing size checks

The command_file_write() handler allocates a kernel buffer of exactly
count bytes and copies user data into it, but does not validate the
buffer against the dot command protocol before passing it to
get_dot_command_size() and get_dot_command_timeout().

Since both the allocation size (count) and the header fields (command_size,
data_size) are independently user-controlled, an attacker can cause
get_dot_command_size() to return a value exceeding the allocation,
triggering OOB reads in get_dot_command_timeout() and an out-of-bounds
memcpy_toio() that leaks kernel heap memory to the service processor.

Fix with two guards: reject writes smaller than sizeof(struct
dot_command_header) before allocation, then after copying user data
reject commands where the buffer is smaller than the total size declared
by the header (sizeof(header) + command_size + data_size). This ensures
all subsequent header and payload field accesses stay within the buffer.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-45994?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-45994?

Apply the vendor's patch.

## Is CVE-2026-45994 being exploited?

There is no known exploitation of CVE-2026-45994 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45994 and fix it if it is affected.

What it is: CVE-2026-45994 is a high-severity vulnerability in Linux kernel, published on 27 May 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-2026-45994 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-45994/ (Markdown: https://insights.sbomify.com/CVE-2026-45994/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45994
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45994
- OSV: https://osv.dev/vulnerability/CVE-2026-45994

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45994/
Summaries are generated and may contain mistakes; the official description above is the record.