High 7.3Published May 21, 2026

CVE-2026-43497fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free

Updated under an hour ago (Oct 27, 2026, 6:30 AM ET)

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Exploited in the last 30 days

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: 7.3 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: Aug 5, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	7433914efd584b22bb49d3e1eee001f5d0525ecd builds before 60f711cfd580f86fea8284146ac133804e728f9a; 7433914efd584b22bb49d3e1eee001f5d0525ecd builds before 5931f5651ee32bd41b3323256b31fcc8e71336ed; from 7433914efd584b22bb49d3e1eee001f5d0525ecd before e3d9865dacd7435b8465848428210d0f0c673311; 7433914efd584b22bb49d3e1eee001f5d0525ecd builds before 4f312c30f0368e8d2a76aa650dff73f23490b5e7; 7433914efd584b22bb49d3e1eee001f5d0525ecd builds before 18dd358de72d57993422cbb5dfb29ccd74efe192; from 7433914efd584b22bb49d3e1eee001f5d0525ecd before da9b065cedfd3b574f229d5be594e6aa47a27ae6; from 7433914efd584b22bb49d3e1eee001f5d0525ecd before a2c53a3822ee26e8d758071815b9ed3bf6669fc1; 7433914efd584b22bb49d3e1eee001f5d0525ecd builds before 8de779dc40d35d39fa07387b6f921eb11df0f511	CNA record
linux linux_kernel linux:linux_kernel	from 4.19 before 5.10.258; from 5.11 before 5.15.209; from 5.16 before 6.1.175; from 6.2 before 6.6.140; from 6.7 before 6.12.88; from 6.13 before 6.18.30; from 6.19 before 7.0.7; 7.1; and 1 more ranges	NVD

References

References

https://git.kernel.org/stable/c/60f711cfd580f86fea8284146ac133804e728f9a	patch
https://git.kernel.org/stable/c/5931f5651ee32bd41b3323256b31fcc8e71336ed	patch
https://git.kernel.org/stable/c/e3d9865dacd7435b8465848428210d0f0c673311	patch
https://git.kernel.org/stable/c/4f312c30f0368e8d2a76aa650dff73f23490b5e7	patch
https://git.kernel.org/stable/c/18dd358de72d57993422cbb5dfb29ccd74efe192	patch
https://git.kernel.org/stable/c/da9b065cedfd3b574f229d5be594e6aa47a27ae6	patch
https://git.kernel.org/stable/c/a2c53a3822ee26e8d758071815b9ed3bf6669fc1	patch
https://git.kernel.org/stable/c/8de779dc40d35d39fa07387b6f921eb11df0f511	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.