Threats Tagged 'cve-2026-43497'

Multiple vulnerabilities affecting the Linux kernel have been identified, including use-after-free bugs and denial of service issues in various kernel components such as bonding driver, erofs filesystem, ALSA 6fire, ip6_tunnel, ipv6 routing, selinux overlayfs, and others. These vulnerabilities impact core Linux kernel functionality across several distributions including Red Hat Enterprise Linux 9 and 10. Security updates addressing these issues have been released by Red Hat and require system reboot to take effect.

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.