Use After Free Affecting kernel-docs package, versions <6.4.0-150700.53.73.1


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.11% (2nd percentile)

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  • Snyk IDSNYK-SLES157-KERNELDOCS-18205747
  • published22 Jul 2026
  • disclosed21 Jul 2026

Introduced: 21 Jul 2026

NewCVE-2026-43497  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade SLES:15.7 kernel-docs to version 6.4.0-150700.53.73.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-docs package and not the kernel-docs package as distributed by SLES. See How to fix? for SLES:15.7 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free

dlfb_ops_mmap() uses remap_pfn_range() to map vmalloc framebuffer pages to userspace but sets no vm_ops on the VMA. This means the kernel cannot track active mmaps. When dlfb_realloc_framebuffer() replaces the backing buffer via FBIOPUT_VSCREENINFO, existing mmap PTEs are not invalidated. On USB disconnect, dlfb_ops_destroy() calls vfree() on the old pages while userspace PTEs still reference them, resulting in a use-after-free: the process retains read/write access to freed kernel pages.

Add vm_operations_struct with open/close callbacks that maintain an atomic mmap_count on struct dlfb_data. In dlfb_realloc_framebuffer(), check mmap_count and return -EBUSY if the buffer is currently mapped, preventing buffer replacement while userspace holds stale PTEs.

Tested with PoC using dummy_hcd + raw_gadget USB device emulation.

CVSS Base Scores

version 3.1