Tracker / CVE-2026-43497
CVE-2026-43497
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.
Prodotti e versioni affette
| linux | linux_kernel |
|---|---|
| linux | linux_kernel · 4.19 → 5.10.258 |
| linux | linux_kernel · 5.11 → 5.15.209 |
| linux | linux_kernel · 5.16 → 6.1.175 |
| linux | linux_kernel · 6.13 → 6.18.30 |
| linux | linux_kernel · 6.19 → 7.0.7 |
| linux | linux_kernel · 6.2 → 6.6.140 |
| linux | linux_kernel · 6.7 → 6.12.88 |