{"id":"CVE-2026-97604","published":"2026-09-25T11:17:14.407","lastModified":"2026-09-25T11:17:14.407","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: vfb: defer cleanup until the last reference\n\nFBIOGETCMAP takes a shallow snapshot of info->cmap and performs the\nusercopy after dropping info->lock. vfb_remove() frees the colormap\nimmediately after unregistering the framebuffer, even when an open file\nstill holds a reference to fb_info. A concurrent driver unbind can\ntherefore free the colormap while the ioctl copies it to userspace.\n\nKASAN reports:\n\n  BUG: KASAN: slab-use-after-free in _copy_to_user\n  Read of size 512 by task poc/125\n\n   _copy_to_user (./include/linux/instrumented.h:129 ./include/linux/uaccess.h:201 lib/usercopy.c:24)\n   fb_cmap_to_user (./include/linux/uaccess.h:230 drivers/video/fbdev/core/fbcmap.c:211)\n   do_fb_ioctl (drivers/video/fbdev/core/fb_chrdev.c:114)\n\n   Allocated by task 1:\n   fb_alloc_cmap_gfp (./include/linux/slab.h:973 ./include/linux/slab.h:1290 drivers/video/fbdev/core/fbcmap.c:108)\n   vfb_probe (drivers/video/fbdev/vfb.c:459)\n\n   Freed by task 124:\n   fb_dealloc_cmap (drivers/video/fbdev/core/fbcmap.c:151)\n   vfb_remove (drivers/video/fbdev/vfb.c:489)\n\nunregister_framebuffer() drops the registration reference, and fbdev calls\nfb_destroy after the last put_fb_info(). Move the registered framebuffer's\ncleanup into an fb_destroy callback so its colormap and screen buffer stay\nalive until all file references have been released.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/3c91e51a53cf805e551e5dc8149cd0539a6dbb9d","tags":[]},{"url":"https://git.kernel.org/stable/c/5ff1effb047e465cde193d7df95988aa1520035e","tags":[]},{"url":"https://git.kernel.org/stable/c/86356f13598f59f5acb1754895747dcdaf65a254","tags":[]},{"url":"https://git.kernel.org/stable/c/a0a34a40ed299c9c7cff6af163a5b883ee9d6d73","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}