# CVE-2026-53325: agp/amd64: Fix broken error propagation in agp_amd64_probe()

> A NULL pointer dereference in the Linux kernel AMD64 AGP driver causes a system crash when running in virtualized environments without physical AMD hardware.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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:** 29 Jun 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-91409, BELL-CVE-2026-53325, DEBIAN-CVE-2026-53325, GHSA-vhjq-v866-4c7f, ROOT-OS-DEBIAN-11-CVE-2026-53325, ROOT-OS-DEBIAN-12-CVE-2026-53325, ROOT-OS-UBUNTU-2204-CVE-2026-53325, ROOT-OS-UBUNTU-2404-CVE-2026-53325, UBUNTU-CVE-2026-53325

## What is CVE-2026-53325?

CVE-2026-53325 is a medium-severity vulnerability in Linux kernel, published on 29 Jun 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:

agp/amd64: Fix broken error propagation in agp_amd64_probe()

A NULL pointer dereference was observed in the AMD64 AGP driver when
running in a virtualized environment (e.g. qemu/kvm) without a physical
AMD northbridge. The crash occurs in amd64_fetch_size() when attempting
to dereference the pointer returned by node_to_amd_nb(0).

The root cause of this crash is broken error propagation in
agp_amd64_probe(): When no AMD northbridges are found, cache_nbs()
correctly returns -ENODEV. However, the probe function erroneously
checks the return value against exactly -1, rather than < 0.

As a result, the hardware absence error is masked, allowing the driver
to improperly proceed with initialization. It eventually calls
agp_add_bridge(), which invokes amd64_fetch_size(). Since the hardware
does not exist, node_to_amd_nb(0) returns NULL, leading to a General
Protection Fault (GPF) when accessing its ->misc member.

Fix the issue by correcting the error check in agp_amd64_probe() to
abort properly when cache_nbs() returns any negative error code. This
prevents the driver from erroneously proceeding without hardware, thereby
avoiding the subsequent NULL pointer dereference at its source.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-53325?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53325?

Apply the vendor's patch.

## Is CVE-2026-53325 being exploited?

There is no known exploitation of CVE-2026-53325 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-2026-53325 and fix it if it is affected.

What it is: CVE-2026-53325 is a medium-severity vulnerability in Linux kernel, published on 29 Jun 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-2026-53325 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-2026-53325/ (Markdown: https://insights.sbomify.com/CVE-2026-53325/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53325
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53325
- OSV: https://osv.dev/vulnerability/CVE-2026-53325

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53325/
Summaries are generated and may contain mistakes; the official description above is the record.