# CVE-2026-63878: drm/amdgpu: check num_entries in GEM_OP GET_MAPPING_INFO

> A local attacker can trigger a kernel panic or warning by supplying an oversized entry count to the amdgpu GEM operation, causing a denial of service.

- **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:** 19 Jul 2026
- **Updated:** 19 Jul 2026
- **Also known as:** BELL-CVE-2026-63878, DEBIAN-CVE-2026-63878, GHSA-7q2q-cf6q-6c84, UBUNTU-CVE-2026-63878

## What is CVE-2026-63878?

CVE-2026-63878 is a vulnerability in Linux, published on 19 Jul 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/amdgpu: check num_entries in GEM_OP GET_MAPPING_INFO

kvcalloc(args->num_entries, sizeof(*vm_entries), GFP_KERNEL) at
amdgpu_gem.c:1050 uses the user-supplied num_entries directly without
any upper bounds check. Since num_entries is a __u32 and
sizeof(drm_amdgpu_gem_vm_entry) is 32 bytes, a large num_entries
produces an allocation exceeding INT_MAX, triggering
WARNING in __kvmalloc_node_noprof(), causing a kernel WARNING,
TAINT_WARN, and panic on CONFIG_PANIC_ON_WARN=y systems.

Add a size bounds check before we invoke the kvzalloc() to
reject oversized num_entries early with -EINVAL.

(cherry picked from commit 1fe7bf5457f6efd7be60b17e23163ba54341d73d)

## Which versions are affected by CVE-2026-63878?


## How do I fix CVE-2026-63878?

Apply the vendor's patch.

## Is CVE-2026-63878 being exploited?

There is no known exploitation of CVE-2026-63878 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63878 and fix it if it is affected.

What it is: CVE-2026-63878 is a vulnerability in Linux, published on 19 Jul 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-2026-63878 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-2026-63878/ (Markdown: https://insights.sbomify.com/CVE-2026-63878/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63878
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63878
- OSV: https://osv.dev/vulnerability/CVE-2026-63878

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63878/
Summaries are generated and may contain mistakes; the official description above is the record.