# CVE-2026-74716: accel/amdxdna: Fix locally exploitable BUG_ON in amdxdna_insert_pages()

> A local attacker can trigger a kernel BUG_ON crash in the AMD XDNA driver by manipulating memory mappings, 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:** 22 Aug 2026
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2026-74716, DEBIAN-CVE-2026-74716, GHSA-44jx-474f-m2qv, UBUNTU-CVE-2026-74716

## What is CVE-2026-74716?

CVE-2026-74716 is a denial of service vulnerability in Linux, published on 22 Aug 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:

accel/amdxdna: Fix locally exploitable BUG_ON in amdxdna_insert_pages()

In amdxdna_insert_pages(), vm_flags_mod() sets VM_MIXEDMAP and clears
VM_PFNMAP. If an unprivileged userspace process mmaps a non-imported GEM
object and then calls madvise(MADV_DONTNEED), the PTEs will be
successfully cleared because VM_MIXEDMAP allows this (unlike VM_PFNMAP).

When userspace subsequently accesses the memory, drm_gem_shmem_fault()
handles the page fault and attempts to map the backing shmem page via
vmf_insert_pfn() which calls vmf_insert_pfn_prot(). Because the backing
shmem page is normal system memory (pfn_valid(pfn) is true) and the VMA
now has VM_MIXEDMAP set, won't this predictably trigger the explicit
assertion BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn))

Fix by removing the vm_flags_mod() call and replacing the vm_insert_pages()
pre-population with the handle_mm_fault() loop that was already used for
the import (dma-buf) path.

## Which versions are affected by CVE-2026-74716?


## How do I fix CVE-2026-74716?

Apply the vendor's patch.

## Is CVE-2026-74716 being exploited?

There is no known exploitation of CVE-2026-74716 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74716 and fix it if it is affected.

What it is: CVE-2026-74716 is a denial of service vulnerability in Linux, published on 22 Aug 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-2026-74716 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-2026-74716/ (Markdown: https://insights.sbomify.com/CVE-2026-74716/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74716
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74716
- OSV: https://osv.dev/vulnerability/CVE-2026-74716

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74716/
Summaries are generated and may contain mistakes; the official description above is the record.