# CVE-2026-98177: drm/amdkfd: Avoid integer underflow in EOP ring size calculation.

> A local attacker with access to AMD GPU hardware could trigger an integer underflow in the kernel driver, potentially causing a system crash.

- **Severity:** Not scored
- **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:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106287, BELL-CVE-2026-98177, DEBIAN-CVE-2026-98177, GHSA-w77g-jh5m-m588, UBUNTU-CVE-2026-98177

## What is CVE-2026-98177?

CVE-2026-98177 is a vulnerability in Linux, published on 6 Oct 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/amdkfd: Avoid integer underflow in EOP ring size calculation.

The low 6 bits of cp_hqd_eop_control store the base-2 logarithm
of the EOP ring size. This was calculated as

order_base_2(q->eop_ring_buffer_size / 4) - 1

But order_base_2 can in theory return 0, so this could underflow
(although in practice the ring buffer size cannot be less than 4096).

Change this to

order_base_2(q->eop_ring_buffer_size / 8)

using properties of logarithms.

Also add to the above comment to make the mathematics more clear.

(cherry picked from commit f0f43fcf8b2b3a924cad9444340921c96ed5f634)

## Which versions are affected by CVE-2026-98177?


## How do I fix CVE-2026-98177?

Apply the vendor's patch.

## Is CVE-2026-98177 being exploited?

There is no known exploitation of CVE-2026-98177 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98177 and fix it if it is affected.

What it is: CVE-2026-98177 is a vulnerability in Linux, published on 6 Oct 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-2026-98177 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-2026-98177/ (Markdown: https://insights.sbomify.com/CVE-2026-98177/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98177
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98177
- OSV: https://osv.dev/vulnerability/CVE-2026-98177

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98177/
Summaries are generated and may contain mistakes; the official description above is the record.