CVE Catalog

CVE-2026-43497

HighCVSS 7.3
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.11%

2th percentile - higher than 2% of all known CVEs

Summary

In the Linux kernel's fbdev udlfb driver, vm_ops are added to dlfb_ops_mmap to prevent use-after-free. Lack of vm_ops allowed stale memory mappings after buffer replacement, leading to access to freed pages.

Risk Assessment

A local attacker could access freed kernel memory, potentially leading to privilege escalation or data leakage.

Recommendation

Update the Linux kernel to a version containing this fix.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS