{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98999", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.385Z", "datePublished": "2026-10-23T12:20:19.451Z", "dateUpdated": "2026-10-24T14:09:56.167Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-24T14:09:56.167Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/xe: Fix stale pinned_link entry when fb-pin performs the final unpin\n\nxe_bo_pin_external() and xe_bo_unpin_external() maintain the bo's\npinned_link list membership in xe->pinned.late.external, based on\nwhether the current call is the outermost pin or the final unpin.\nHowever, the same external bo's pin_count can also be raised and\nlowered directly by __xe_pin_fb_vma()/__xe_unpin_fb_vma(), which pin\nthe bo as a display scanout buffer without going through\nxe_bo_pin_external()/xe_bo_unpin_external() at all, and have no\nnotion of, or ownership over, pinned_link.\n\nIf a bo is pinned both externally (e.g. dma-buf export) and as an fb,\nand the external unpin happens first, xe_bo_unpin_external() correctly\nobserves pin_count > 1 and leaves the bo on pinned_link. When the fb\nunpin later performs the true last unpin (pin_count 1 -> 0), it never\ntouches pinned_link, leaving the bo linked on xe->pinned.late.external\nindefinitely. Once the bo is subsequently freed, this stale list entry\npoints into freed memory, corrupting the list and risking a\nuse-after-free the next time the list is walked or spliced.\n\nThe backup object pin/unpin sites in xe_bo_notifier_prepare_pinned()/\nxe_bo_notifier_unprepare_pinned() have the same bypass characteristic,\nthough they never add their bo to a pinned list, so are not affected\nby this particular list-corruption issue.\n\nMove the pinned_link removal into xe_bo_account_unpin(), which already\nruns on every unpin path (kernel, external, framebuffer, backup\nobject) right before the true 1 -> 0 pin_count transition. Since\nlist_del_init() only operates on the node itself, this removal is\nlist-agnostic and safe to perform regardless of which list (external\nor kernel_bo_present) the bo happens to be linked on, or which code\npath is performing the final unpin. Drop the now-redundant explicit\nlist_del_init() calls in xe_bo_unpin_external() and xe_bo_unpin().\n\nv2:\n- New patch\n\nv3:\n- Rebased on changes to previous patch.\n\n(cherry picked from commit ca58d36a1f93af586ee93b340c9f9fd81312cc01)" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Local DRM ioctls reach patched xe_bo_account_unpin(): DRM_IOCTL_MODE_ATOMIC -> intel_atomic_commit -> intel_cleanup_plane_fb -> __xe_unpin_fb_vma -> xe_bo_unpin_account -> xe_bo_account_unpin; DRM_IOCTL_PRIME_FD_TO_HANDLE creates the competing pin through xe_dma_buf_pin().\nAC:L - On a hybrid-GPU host, one client can import the exported Xe BO, scan it out, close the import so xe_bo_unpin_external() runs at pin_count 2, disable the plane for the final fb unpin, free the BO, and pin another BO to touch the stale list. No race or independent actor is required.\nPR:L - XE_GEM_CREATE and both PRIME ioctls are DRM_RENDER_ALLOW; DRM_MODE_ATOMIC requires DRM_MASTER, but drm_master_open() makes the first primary-node opener master when none exists without CAP_SYS_ADMIN. An unprivileged user granted the DRM device nodes therefore suffices.\nUI:N - The same process issues the PRIME, atomic modeset/disable, and close operations; no victim must mount, open, or approve anything.\nS:U - The freed xe_bo and xe->pinned.late.external are kernel-owned objects, and xe_bo_apply_to_pinned() corrupts memory within the same host kernel; no guest/host, IOMMU, or other security authority is crossed.\nC:H - After xe_ttm_bo_destroy() frees an xe_bo still linked by pinned_link, xe_bo_apply_to_pinned() treats reclaimed slab contents as a live BO and eviction reads its resource, reservation, backup_obj, and flags pointers. This exploitable UAF supports arbitrary kernel-memory disclosure.\nI:H - xe_bo_apply_to_pinned() calls list_move_tail() on the freed pinned_link; after heap reclaim, its attacker-shaped prev/next pointers feed list deletion writes, enabling arbitrary kernel-memory corruption and potential control-flow hijacking.\nA:H - Reusing or walking xe->pinned.late.external after kfree(bo), through another xe_bo_pin_external() or xe_bo_apply_to_pinned(), dereferences and writes freed memory, corrupting the list and causing an oops or kernel panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/gpu/drm/xe/xe_bo.c" ], "versions": [ { "version": "44e694958b95395bd1c41508c88c8ca141bf9bd7", "lessThan": "3a11adcfd9a2de74d405bd3e8c4d7a1b328e4684", "status": "affected", "versionType": "git" }, { "version": "44e694958b95395bd1c41508c88c8ca141bf9bd7", "lessThan": "b3eaff982839e5c22912d604cd8e7748cece8d63", "status": "affected", "versionType": "git" }, { "version": "44e694958b95395bd1c41508c88c8ca141bf9bd7", "lessThan": "cf238c067eaae1cbfb00738e29219b9568d2313e", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/gpu/drm/xe/xe_bo.c" ], "versions": [ { "version": "6.8", "status": "affected" }, { "version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.11", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.2.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/3a11adcfd9a2de74d405bd3e8c4d7a1b328e4684" }, { "url": "https://git.kernel.org/stable/c/b3eaff982839e5c22912d604cd8e7748cece8d63" }, { "url": "https://git.kernel.org/stable/c/cf238c067eaae1cbfb00738e29219b9568d2313e" } ], "title": "drm/xe: Fix stale pinned_link entry when fb-pin performs the final unpin", "x_generator": { "engine": "bippy-1.2.0" } } } }