{"id":"CVE-2026-98166","title":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/ttm: fix swapped-out resources never leaving their bulk_move range\n\nttm_tt_swapout() returns the number of pages swapped out on success and\na negative error code on…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/ttm: fix swapped-out resources never leaving their bulk_move range\n\nttm_tt_swapout() returns the number of pages swapped out on success and\na negative error code on…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-825"],"vendor":"Linux","product":"Linux","affected":["Linux >= b2ed01e7ad3de80333e9b962a44024b094bc0b2b < 1169fe8c11ca45e3f91d59a73eb271d0ca8a7fb0","Linux >= b2ed01e7ad3de80333e9b962a44024b094bc0b2b < 3db7d7d583419f7b1f2e141e36418802dbb25cf8","Linux 0124a09e3e5f5f6080efe9663b27af27933f8382","Linux >= 7.0.10 < 7.1","Linux 7.1"],"published":"2026-10-06","updated":"2026-10-15","sourceUpdated":"2026-10-15T11:18:12.190","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98166","references":[{"url":"https://git.kernel.org/stable/c/1169fe8c11ca45e3f91d59a73eb271d0ca8a7fb0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3db7d7d583419f7b1f2e141e36418802dbb25cf8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98166.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-98166"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2546426"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98166"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98166"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98166.mbox"},{"url":"https://git.kernel.org/stable/c/b48ebe399b4e72baa323462580fdd83ebda561e1"}],"tags":["nvd","cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00157,"epssPercentile":0.04803,"scores":{"nvd":7.8,"vendor":5.5,"cna":7.8},"ingestedAt":"2026-10-06T08:50:17.459Z","slug":"CVE-2026-98166","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ndrm/ttm: fix swapped-out resources never leaving their bulk_move range\n\nttm_tt_swapout() returns the number of pages swapped out on success and\na negative error code on failure; for a populated ttm it never returns\nzero. Commit b2ed01e7ad3d (\"drm/ttm: Fix ttm_bo_swapout() infinite LRU\nwalk on swapout failure\") moved the bulk_move bookkeeping in\nttm_bo_swapout_cb() under \"if (!ret)\", so the\nttm_resource_del_bulk_move_unevictable() / ttm_resource_move_to_lru_tail()\npair is now skipped on every successful swapout. The equivalent change\nfor the shrinker in commit 1d59f36e95f7 (\"drm/ttm: Fix ttm_bo_shrink()\ninfinite LRU walk on backup failure\") tests \"lret > 0\", which is what\nwas intended here as well.\n\nBefore b2ed01e7ad3d the resource was taken off the bulk_move before the\nswapout; since then a swapped-out resource stays inside its BO's\nbulk_move range (and on the manager LRU) although it is unevictable.\nWhen it is later freed or the BO leaves the bulk_move\n(ttm_resource_free(), ttm_bo_set_bulk_move() via amdgpu_vm_bo_del()),\nttm_resource_del_bulk_move() skips it because of its\n!ttm_resource_unevictable() guard, so a range endpoint in pos->first /\npos->last is left pointing at freed memory. The next\nttm_lru_bulk_move_tail() or ttm_resource_add_bulk_move() on that cursor\nis a use-after-free, seen as the resv WARN in ttm_lru_bulk_move_add(),\n\"list_del corruption\" in ttm_resource_move_to_lru_tail() or a NULL\ndereference in ttm_resource_manager_next() -- minutes to hours after a\nhibernation, or at process exit / reboot following one. Samuel\nAinsworth's analysis of drm/amd issue 5387 (see Link) identified the\ndangling cursor; the missing removal at swapout time is the reason it\ndangles.\n\nTesting the condition for success restores the removal. On an AMD\nPhoenix APU (ASUS UM3406GA, gfx1103) running suspend-then-hibernate on\na 7.0.y stable kernel carrying the backport (Ubuntu 7.0.0-31) the bug\ncrashed 5 of 18 hibernation cycles; a function profile of one\nhibernation showed 336 ttm_tt_swapout() calls and zero\nttm_resource_del_bulk_move_unevictable() calls. With this change the\nremoval happens for every swapped-out resource and 12 further cycles\nwere clean.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-10-07 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98166.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":217258,"id":"CVE-2026-98166","ts":1791361301141,"field":"cvss","old":"5.5","new":"7.8"},{"seq":217257,"id":"CVE-2026-98166","ts":1791361301141,"field":"severity","old":"medium","new":"high"},{"seq":217091,"id":"CVE-2026-98166","ts":1791360667847,"field":"cvss","old":null,"new":"5.5"},{"seq":217090,"id":"CVE-2026-98166","ts":1791360667847,"field":"severity","old":"none","new":"medium"}]}