CVSS 7.3 · High EPSS 0,17%
Kerentanan Use After Free pada linux kernel. Skor CVSS 3.1 7.3 (High) menurut CNA.
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:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
· uraikan di kalkulator | Vendor | Produk | Versi terdampak |
|---|---|---|
| linux | linux kernel | Versi 4.19 hingga sebelum 5.10.258 |
| linux | linux kernel | Versi 5.11 hingga sebelum 5.15.209 |
| linux | linux kernel | Versi 5.16 hingga sebelum 6.1.175 |
| linux | linux kernel | Versi 6.2 hingga sebelum 6.6.140 |
| linux | linux kernel | Versi 6.7 hingga sebelum 6.12.88 |
| linux | linux kernel | Versi 6.13 hingga sebelum 6.18.30 |
| linux | linux kernel | Versi 6.19 hingga sebelum 7.0.7 |
| linux | linux kernel | Versi 7.1 rc1 |
| linux | linux kernel | Versi 7.1 rc2 |