fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free (Linux Linux)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.11 % · percentile 1 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Linux
- NVD status
- Analyzed
Description
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.
Weaknesses (CWE)
- CWE-416 — Use After Free
References
- https://git.kernel.org/stable/c/60f711cfd580f86fea8284146ac133804e728f9a
- https://git.kernel.org/stable/c/5931f5651ee32bd41b3323256b31fcc8e71336ed
- https://git.kernel.org/stable/c/e3d9865dacd7435b8465848428210d0f0c673311
- https://git.kernel.org/stable/c/4f312c30f0368e8d2a76aa650dff73f23490b5e7
- https://git.kernel.org/stable/c/18dd358de72d57993422cbb5dfb29ccd74efe192
- https://git.kernel.org/stable/c/da9b065cedfd3b574f229d5be594e6aa47a27ae6
- https://git.kernel.org/stable/c/a2c53a3822ee26e8d758071815b9ed3bf6669fc1
- https://git.kernel.org/stable/c/8de779dc40d35d39fa07387b6f921eb11df0f511
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.3 | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H | Linux |
| CVSS 3.1 | HIGH 7.3 | CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H | NVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary) |
European references
- ENISA EUVD · EUVD-2026-31273
- GCVE · GCVE-0-2026-43497
CERT-FR advisories
- CERTFR-2026-AVI-1252 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1229 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1162 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1093 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1066 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0985 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0954 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0927 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0926 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0862 — Multiples vulnérabilités dans le noyau Linux de Debian LTS · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 4.19 < 5.10.258cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.11 < 5.15.209cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 5.16 < 6.1.175cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.2 < 6.6.140cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.7 < 6.12.88cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.13 < 6.18.30cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.19 < 7.0.7cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Linux · Linux | affected 7433914efd584b22bb49d3e1eee001f5d0525ecd < 60f711cfd580f86fea8284146ac133804e728f9a ; affected 7433914efd584b22bb49d3e1eee001f5d0525ecd < 5931f5651ee32bd41b3323256b31fcc8e71336ed ; affected 7433914efd584b22bb49d3e1eee001f5d0525ecd < e3d9865dacd7435b8465848428210d0f0c673311 ; affected 7433914efd584b22bb49d3e1eee001f5d0525ecd < 4f312c30f0368e8d2a76aa650dff73f23490b5e7 ; affected 7433914efd584b22bb49d3e1eee001f5d0525ecd < 18dd358de72d57993422cbb5dfb29ccd74efe192 ; affected 7433914efd584b22bb49d3e1eee001f5d0525ecd < da9b065cedfd3b574f229d5be594e6aa47a27ae6 |
| Linux · Linux | affected 4.19 ; unaffected 0 < 4.19 ; unaffected 5.10.258 ≤ 5.10.* ; unaffected 5.15.209 ≤ 5.15.* ; unaffected 6.1.175 ≤ 6.1.* ; unaffected 6.6.140 ≤ 6.6.* |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |