{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68266", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.378Z", "datePublished": "2026-08-10T12:01:41.280Z", "dateUpdated": "2026-08-17T05:01:59.066Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:01:59.066Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/xe: Hold a dma-buf reference for imported BOs\n\nAn imported dma-buf BO is created as a ttm_bo_type_sg BO whose\nreservation object is the exporter's dma_buf->resv. The importer,\nhowever, only takes a dma-buf reference after a successful\ndma_buf_dynamic_attach(). Until then nothing keeps the exporter alive,\nso if the exporter is freed while the BO still references its resv, a\nlater access to that resv is a use-after-free:\n\n Oops: general protection fault, probably for non-canonical address\n 0x6b6b6b6b6b6b6b9c\n Workqueue: ttm ttm_bo_delayed_delete [ttm]\n RIP: 0010:mutex_can_spin_on_owner+0x3f/0xc0\n\nThis can be reached on two paths:\n\n - dma_buf_dynamic_attach() fails, or\n - ttm_bo_init_reserved() fails during BO creation.\n\nIn both cases the BO already has bo->base.resv pointing at the exporter\nresv, and sg BOs are always torn down via ttm_bo_delayed_delete(), which\nlocks bo->base.resv asynchronously - potentially after the exporter has\nbeen freed.\n\nTake the dma-buf reference in xe_bo_init_locked(), before\nttm_bo_init_reserved(), so it also covers a creation failure there, and\nrelease it in xe_ttm_bo_destroy(). The reference is held for the whole\nBO lifetime, keeping the shared resv alive on every path.\n\nv2:\n - Reworked the fix to avoid creating the imported sg BO before\n dma_buf_dynamic_attach() succeeds.\n - Attach with importer_priv == NULL and make invalidate_mappings ignore\n incomplete imports.\n\nv3:\n - Dropped the xe-side reordering approach since importer_priv must be\n valid when dma_buf_dynamic_attach() publishes the attachment.\n - Per Christian's suggestion on the v1 thread, keyed the check on\n import_attach rather than removing the sg guard entirely.\n - Fixes both xe and amdgpu in a single TTM patch.\n\nv4:\n - Moved import_attach check to after dma_resv_copy_fences() so fences\n are copied before returning for successful imports (Thomas).\n - Removed exporter-alive claim from commit message (Thomas).\n\nv5:\n - Add drm/xe patch to keep imported sg BOs off the LRU before attach\n succeeds; the TTM fix alone is not sufficient for xe if the BO is\n already LRU-visible. (Thomas)\n v4 patch:\n https://patchwork.freedesktop.org/patch/736663/?series=169129&rev=2\n - Patch 1 (drm/ttm) carries Christian's Reviewed-by from v4.\n\nv6:\n - Reworked the fix based on Thomas' suggestion. Instead of the TTM resv\n individualization (v1-v5) plus the xe off-LRU/placement handling (v5),\n just hold a dma-buf reference for the imported BO lifetime so the\n shared resv can never be freed while the BO still references it.\n Single xe patch, no TTM change. (Thomas)\n - Take the reference in xe_bo_init_locked() before ttm_bo_init_reserved()\n so a TTM creation failure is covered too (Thomas).\n - Dropped the v5 series (drm/ttm + drm/xe off-LRU); the off-LRU approach\n also regressed in CI BAT via ttm_bo_pipeline_gutting() creating a ghost\n BO that outlived the exporter.\n Link to v5: https://patchwork.freedesktop.org/series/169984/\n\nv7:\n - Move changelog above --- so it stays in the commit message.\n - Reorder changelog entries oldest-to-newest. (Thomas)\n\n(cherry picked from commit 3516f3fae6be35642f8f06f8a218da6425c0306a)" } ], "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 - The bug is reached through DRM_IOCTL_PRIME_FD_TO_HANDLE on an Intel xe DRM render node (/dev/dri/renderD*), which requires local access to the device file; there is no remote or network-facing path into xe_gem_prime_import().\nAC:L - The attacker fully controls both halves: they pick an exporter whose attach fails deterministically (drm_gem_map_attach() returns -ENOSYS, xe_dma_buf_attach() returns -EOPNOTSUPP for non-p2p cross-device imports) or induce the -ENOMEM paths, then simply close the dma-buf fd while the sg BO teardown is still queued on the TTM workqueue. No condition outside their control is needed.\nPR:L - DRM_IOCTL_PRIME_FD_TO_HANDLE is marked DRM_RENDER_ALLOW, so any unprivileged local user holding the normally world/group-accessible render node (any GUI user on a distro, any app on Android/ChromeOS) can perform the import; no capabilities are checked.\nUI:N - The entire sequence — export a dma-buf, import it into xe, close the fd — is performed by the attacker's own process; no victim action or cooperation is required.\nS:U - The use-after-free occurs on kernel heap memory within the same kernel security authority; there is no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The freed dma_buf/dma_resv is a slab object the attacker can reclaim with sprayed content before ttm_bo_delayed_delete() dereferences it, so the stale bo->base.resv can be aimed at attacker-chosen kernel addresses and the resulting ww_mutex/fence walks leaked back, giving arbitrary kernel memory disclosure.\nI:H - dma_resv_lock()/dma_resv_unlock() and the subsequent ttm_bo_cleanup_memtype_use() perform writes and list manipulation through the dangling pointer into reclaimed heap memory, so the UAF yields a controllable write primitive usable for control-flow hijacking and privilege escalation.\nA:H - Even unexploited, the flaw reliably produces a kernel oops — the reported general protection fault on poisoned memory in mutex_can_spin_on_owner() from the ttm workqueue — which is a fatal fault in kernel worker context and takes down the GPU stack or the whole machine." } ] } ], "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", "drivers/gpu/drm/xe/xe_bo.h", "drivers/gpu/drm/xe/xe_bo_types.h", "drivers/gpu/drm/xe/xe_dma_buf.c" ], "versions": [ { "version": "dd08ebf6c3525a7ea2186e636df064ea47281987", "lessThan": "c22d65d62b3318e237c0e5b1177d90ab83d9fe06", "status": "affected", "versionType": "git" }, { "version": "dd08ebf6c3525a7ea2186e636df064ea47281987", "lessThan": "c1954c66662de477a8f4309335b775f7b07bd28b", "status": "affected", "versionType": "git" }, { "version": "dd08ebf6c3525a7ea2186e636df064ea47281987", "lessThan": "ba8c4cbb31c6f81fa5b12d6e28f1f706040aff48", "status": "affected", "versionType": "git" }, { "version": "dd08ebf6c3525a7ea2186e636df064ea47281987", "lessThan": "62775525a27c3b0d56382e08ba81ee2d322058b6", "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", "drivers/gpu/drm/xe/xe_bo.h", "drivers/gpu/drm/xe/xe_bo_types.h", "drivers/gpu/drm/xe/xe_dma_buf.c" ], "versions": [ { "version": "6.8", "status": "affected" }, { "version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.103", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.42", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.6", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "6.12.103" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.18.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.1.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/c22d65d62b3318e237c0e5b1177d90ab83d9fe06" }, { "url": "https://git.kernel.org/stable/c/c1954c66662de477a8f4309335b775f7b07bd28b" }, { "url": "https://git.kernel.org/stable/c/ba8c4cbb31c6f81fa5b12d6e28f1f706040aff48" }, { "url": "https://git.kernel.org/stable/c/62775525a27c3b0d56382e08ba81ee2d322058b6" } ], "title": "drm/xe: Hold a dma-buf reference for imported BOs", "x_generator": { "engine": "bippy-1.2.0" } } } }