{"id":"CVE-2026-98523","title":"drm/client: fix restore of partially initialized client","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/client: fix restore of partially initialized client\n\nI got a null-ptr-deref report when closing a DRM file descriptor:\n\nWARNING: drivers/gpu/drm/drm_atomic.c:2031 a…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 7f5535fcbba2ce7f1908ee7e5c350032a4b1e9d0 < 11edd5b6735d2e1069ddce672b1836713647f7fb","Linux >= 5d08c44e47b9d41366714552bdd374ac4b595591 < fcbedba553a9c430079ee225df2dc7ab556a2f83","Linux >= 5d08c44e47b9d41366714552bdd374ac4b595591 < a69c4b678db808c0d89abb8cedeaaac38d1ef182","Linux >= 5d08c44e47b9d41366714552bdd374ac4b595591 < 1fca688e9443003e33cf30453e7a7560367656c9","Linux >= 6.12.19 < 6.12.112","Linux 6.13"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:17:40.598Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98523","references":[{"url":"https://git.kernel.org/stable/c/11edd5b6735d2e1069ddce672b1836713647f7fb"},{"url":"https://git.kernel.org/stable/c/fcbedba553a9c430079ee225df2dc7ab556a2f83"},{"url":"https://git.kernel.org/stable/c/a69c4b678db808c0d89abb8cedeaaac38d1ef182"},{"url":"https://git.kernel.org/stable/c/1fca688e9443003e33cf30453e7a7560367656c9"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T15:45:12.282Z","slug":"CVE-2026-98523","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ndrm/client: fix restore of partially initialized client\n\nI got a null-ptr-deref report when closing a DRM file descriptor:\n\nWARNING: drivers/gpu/drm/drm_atomic.c:2031 at\n__drm_atomic_helper_set_config+0x18e/0x1b0 [drm]\n\nCall Trace:\ndrm_client_modeset_commit_atomic+0x16b/0x220 [drm]\ndrm_client_modeset_commit_locked+0x56/0x160 [drm]\ndrm_client_modeset_commit+0x21/0x40 [drm]\n__drm_fb_helper_restore_fbdev_mode_unlocked.part.0+0x7b/0x80\ndrm_fbdev_client_restore+0xe/0x20 [drm_client_lib]\ndrm_client_dev_restore+0x9f/0xc0 [drm]\ndrm_release+0xc5/0xe0 [drm]\n\nThe warning is followed by a NULL pointer dereference:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000008\n\nRIP:\n__drm_fb_helper_restore_fbdev_mode_unlocked.part.0+0x41/0x80\n[drm_kms_helper]\n\nCall Trace:\ndrm_fbdev_client_restore+0xe/0x20 [drm_client_lib]\ndrm_client_dev_restore+0x9f/0xc0 [drm]\ndrm_release+0xc5/0xe0 [drm]\n__fput+0xdc/0x2b0\n__x64_sys_close+0x39/0x80\ndo_syscall_64+0x8d/0x460\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\n\ndrm_client_register() adds the DRM client to the device client list\nbefore invoking the initial hotplug callback. If the hotplug callback\nfails, the client remains registered.\n\nFor the fbdev client, a failure during drm_fb_helper_initial_config()\ncauses the partially initialized fbdev helper to be cleaned up.\ndrm_fb_helper_fini() releases fb_helper->info and leaves it NULL.\n\nThe fbdev client therefore remains registered even though there is no\nfully initialized framebuffer device.\n\nLater, when userspace closes the DRM file descriptor, drm_release()\ncan invoke the restore callbacks of registered DRM clients:\n\ndrm_release()\ndrm_client_dev_restore()\ndrm_fbdev_client_restore()\ndrm_fb_helper_restore_fbdev_mode_unlocked()\n\ndrm_fbdev_client_restore() currently restores the fbdev state\nunconditionally. For a partially initialized fbdev client this can\nsubmit an incomplete modeset state and subsequently access fbdev\nstate which has not been initialized, resulting in the warning and\nNULL pointer dereference above.\n\ndrm_fbdev_client_unregister() already uses fb_helper->info to\ndistinguish a fully probed framebuffer device from a partially\ninitialized client.\n\nUse the same condition in drm_fbdev_client_restore() and skip restore\nif no framebuffer device has been successfully initialized.\n\n## Affected\n\n- `Linux >= 7f5535fcbba2ce7f1908ee7e5c350032a4b1e9d0 < 11edd5b6735d2e1069ddce672b1836713647f7fb`\n- `Linux >= 5d08c44e47b9d41366714552bdd374ac4b595591 < fcbedba553a9c430079ee225df2dc7ab556a2f83`\n- `Linux >= 5d08c44e47b9d41366714552bdd374ac4b595591 < a69c4b678db808c0d89abb8cedeaaac38d1ef182`\n- `Linux >= 5d08c44e47b9d41366714552bdd374ac4b595591 < 1fca688e9443003e33cf30453e7a7560367656c9`\n- `Linux >= 6.12.19 < 6.12.112`\n- `Linux 6.13`\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":[]}