CVE-2026-68266
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: drm/xe: Hold a dma-buf reference for imported BOs An imported dma-buf BO is created as a ttm_bo_type_sg BO whose reservation object is the exporter's dma_buf->resv. The importer, however, only takes a dma-buf reference after a successful dma_buf_dynamic_attach(). Until then nothing keeps the exporter alive, so if the exporter is freed while the BO still references its resv, a later access to that resv is a use-after-free: Oops: general protection fault, probably for non-canonical address 0x6b6b6b6b6b6b6b9c Workqueue: ttm ttm_bo_delayed_delete [ttm] RIP: 0010:mutex_can_spin_on_owner+0x3f/0xc0 This can be reached on two paths: - dma_buf_dynamic_attach() fails, or - ttm_bo_init_reserved() fails during BO creation. In both cases the BO already has bo->base.resv pointing at the exporter resv, and sg BOs are always torn down via ttm_bo_delayed_delete(), which locks bo->base.resv asynchronously - potentially after the exporter has been freed. Take the dma-buf reference in xe_bo_init_locked(), before ttm_bo_init_reserved(), so it also covers a creation failure there, and release it in xe_ttm_bo_destroy(). The reference is held for the whole BO lifetime, keeping the shared resv alive on every path. v2: - Reworked the fix to avoid creating the imported sg BO before dma_buf_dynamic_attach() succeeds. - Attach with importer_priv == NULL and make invalidate_mappings ignore incomplete imports. v3: - Dropped the xe-side reordering approach since importer_priv must be valid when dma_buf_dynamic_attach() publishes the attachment. - Per Christian's suggestion on the v1 thread, keyed the check on import_attach rather than removing the sg guard entirely. - Fixes both xe and amdgpu in a single TTM patch. v4: - Moved import_attach check to after dma_resv_copy_fences() so fences are copied before returning for successful imports (Thomas). - Removed exporter-alive claim from commit message (Thomas). v5: - Add drm/xe patch to keep imported sg BOs off the LRU before attach succeeds; the TTM fix alone is not sufficient for xe if the BO is already LRU-visible. (Thomas) v4 patch: https://patchwork.freedesktop.org/patch/736663/?series=169129&rev=2 - Patch 1 (drm/ttm) carries Christian's Reviewed-by from v4. v6: - Reworked the fix based on Thomas' suggestion. Instead of the TTM resv individualization (v1-v5) plus the xe off-LRU/placement handling (v5), just hold a dma-buf reference for the imported BO lifetime so the shared resv can never be freed while the BO still references it. Single xe patch, no TTM change. (Thomas) - Take the reference in xe_bo_init_locked() before ttm_bo_init_reserved() so a TTM creation failure is covered too (Thomas). - Dropped the v5 series (drm/ttm + drm/xe off-LRU); the off-LRU approach also regressed in CI BAT via ttm_bo_pipeline_gutting() creating a ghost BO that outlived the exporter. Link to v5: https://patchwork.freedesktop.org/series/169984/ v7: - Move changelog above --- so it stays in the commit message. - Reorder changelog entries oldest-to-newest. (Thomas) (cherry picked from commit 3516f3fae6be35642f8f06f8a218da6425c0306a)
View original CVE JSON
{
"id": "CVE-2026-68266",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-08-10T13:20:15.493",
"lastModified": "2026-10-19T21:18:00.230",
"vulnStatus": "Received",
"cveTags": [],
"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)"
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"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"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "dd08ebf6c3525a7ea2186e636df064ea47281987",
"lessThan": "c22d65d62b3318e237c0e5b1177d90ab83d9fe06",
"versionType": "git",
"status": "affected"
},
{
"version": "dd08ebf6c3525a7ea2186e636df064ea47281987",
"lessThan": "c1954c66662de477a8f4309335b775f7b07bd28b",
"versionType": "git",
"status": "affected"
},
{
"version": "dd08ebf6c3525a7ea2186e636df064ea47281987",
"lessThan": "ba8c4cbb31c6f81fa5b12d6e28f1f706040aff48",
"versionType": "git",
"status": "affected"
},
{
"version": "dd08ebf6c3525a7ea2186e636df064ea47281987",
"lessThan": "62775525a27c3b0d56382e08ba81ee2d322058b6",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"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"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "6.8",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.8",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.103",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.42",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.1.6",
"lessThanOrEqual": "7.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"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",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-10-16T15:46:26.487807Z",
"id": "CVE-2026-68266",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-416"
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/62775525a27c3b0d56382e08ba81ee2d322058b6",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ba8c4cbb31c6f81fa5b12d6e28f1f706040aff48",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c1954c66662de477a8f4309335b775f7b07bd28b",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c22d65d62b3318e237c0e5b1177d90ab83d9fe06",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}