fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-416 and the CVSS impact.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 4.19 and later | 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7, 7.1 | Patch available | CNA |
- Linux VendorLinux Affected 4.19 and later 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 Patch available CNA
CPE configurations NVD · 3
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 4.19 to before 5.10.258; 5.11 to before 5.15.209; 5.16 to before 6.1.175; 6.2 to before 6.6.140; 6.7 to before 6.12.88; 6.13 to before 6.18.30; 6.19 to before 7.0.7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* | 7.1 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* | 7.1 rc2 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.19 to before 5.10.258; 5.11 to before 5.15.209; 5.16 to before 6.1.175; 6.2 to before 6.6.140; 6.7 to before 6.12.88; 6.13 to before 6.18.30; 6.19 to before 7.0.7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* Versions 7.1 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* Versions 7.1 rc2 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) 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
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 5 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-43497
- 2026-10-03 Alias added: GHSA-233x-r9gj-mfg9
- 2026-10-20 Affected versions changed · Red Hat
References
Patch 8
- 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
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Sources
- CVE-2026-43497 · CVE Program
- CVE-2026-43497 · NVD
- FIRST EPSS
- GHSA-233x-r9gj-mfg9 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-43497 · Red Hat security data · CC BY 4.0
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