{"id":"CVE-2026-97604","title":"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","summary":"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()…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 5e266e2e0e19532c1b8e2e2bff1eb6ccf42e478a < 86356f13598f59f5acb1754895747dcdaf65a254","Linux >= 5e266e2e0e19532c1b8e2e2bff1eb6ccf42e478a < 5ff1effb047e465cde193d7df95988aa1520035e","Linux >= 5e266e2e0e19532c1b8e2e2bff1eb6ccf42e478a < 3c91e51a53cf805e551e5dc8149cd0539a6dbb9d","Linux >= 5e266e2e0e19532c1b8e2e2bff1eb6ccf42e478a < a0a34a40ed299c9c7cff6af163a5b883ee9d6d73","Linux 2.6.30"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T11:17:14.407","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97604","references":[{"url":"https://git.kernel.org/stable/c/3c91e51a53cf805e551e5dc8149cd0539a6dbb9d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5ff1effb047e465cde193d7df95988aa1520035e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/86356f13598f59f5acb1754895747dcdaf65a254","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a0a34a40ed299c9c7cff6af163a5b883ee9d6d73","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-25T11:06:38.901Z","slug":"CVE-2026-97604","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}