{"schema":"threatline.record/2","record":{"id":"CVE-2026-98523","aliases":[],"summary":"drm/client: fix restore of partially initialized client","details":"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 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.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98523","source_modified_at":"2026-10-19T09:21:05.087Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"7f5535fcbba2ce7f1908ee7e5c350032a4b1e9d0","lessThan":"11edd5b6735d2e1069ddce672b1836713647f7fb","status":"affected","versionType":"git"},{"version":"5d08c44e47b9d41366714552bdd374ac4b595591","lessThan":"fcbedba553a9c430079ee225df2dc7ab556a2f83","status":"affected","versionType":"git"},{"version":"5d08c44e47b9d41366714552bdd374ac4b595591","lessThan":"a69c4b678db808c0d89abb8cedeaaac38d1ef182","status":"affected","versionType":"git"},{"version":"5d08c44e47b9d41366714552bdd374ac4b595591","lessThan":"1fca688e9443003e33cf30453e7a7560367656c9","status":"affected","versionType":"git"},{"version":"6.12.19","lessThan":"6.12.112","status":"affected","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98523","source_modified_at":"2026-10-19T09:21:05.087Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"6.13","status":"affected"},{"version":"0","lessThan":"6.13","status":"unaffected","versionType":"semver"},{"version":"6.12.112","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.55","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.9","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98523","source_modified_at":"2026-10-19T09:21:05.087Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"11edd5b6735d2e1069ddce672b1836713647f7fb","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98523","source_modified_at":"2026-10-19T09:21:05.087Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"1fca688e9443003e33cf30453e7a7560367656c9","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98523","source_modified_at":"2026-10-19T09:21:05.087Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"6.12.112","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00209,"percentile":0.10474,"score_date":"2026-10-23"},"published_at":"2026-10-18T15:17:40.598Z","modified_at":"2026-10-19T09:21:05.087Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98523","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:21:05.087Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98523","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/11edd5b6735d2e1069ddce672b1836713647f7fb"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/fcbedba553a9c430079ee225df2dc7ab556a2f83"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/a69c4b678db808c0d89abb8cedeaaac38d1ef182"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/1fca688e9443003e33cf30453e7a7560367656c9"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:21:05.087Z","content_hash":"1831b1802ae87de39606a3c79b8f62f1725b61256f319908fec6568cdf6a2823"}}