CVE-2026-43497

High

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.

Package Linux Kernel
Published 2026-05-21
Last modified 2026-06-01
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.3

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 4.19 and later are affected. Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7, 7.1-rc3 and their respective stable series.

Affected from
≥ 4.19
Fixed in
✓ 5.10.258 5.10.x ✓ 5.15.209 5.15.x ✓ 6.1.175 6.1.x ✓ 6.6.140 6.6.x ✓ 6.12.88 6.12.x ✓ 6.18.30 6.18.x ✓ 7.0.7 7.0.x ✓ 7.1-rc3

References

The following references provide additional information about CVE-2026-43497 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

8 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2026-43497?

    CVE-2026-43497 is a High severity Linux kernel vulnerability with a CVSS score of 7.3 out of 10 . It affects Linux kernel versions from 4.19 onward and has been patched in 5.10.258, 5.15.209, 6.1.175 and others. CVE-2026-43497 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-43497?

    CVE-2026-43497 has a CVSS score of 7.3 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-43497?

    Yes — CVE-2026-43497 has been patched. Fixed versions include 5.10.258, 5.15.209, 6.1.175 and others. If you are running Linux kernel 4.19 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-43497 actively exploited?

    No — CVE-2026-43497 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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