---
cve: "CVE-2026-74716"
severity: "LOW"
cvss: 3.1
epss: "0.2%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-08-22 16:16:46"
tags: [cve, security, low]
source: tsecurity.de CVE-Dossier
exported: "2026-09-26T06:52:25+02:00"
---

# CVE-2026-74716

> 3.1 LOW

## Beschreibung

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.

## Patch verfügbar (OSV)

- Kernel ≥ 7.1.9

## Referenzen

- <https://git.kernel.org/stable/c/13339132d89d00b513dff0730bff3a313b9b13b5>
- <https://git.kernel.org/stable/c/4a19f7ab5972ef608b31ae921419bc3e04b3f8ad>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-74716) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_