Vulnerability-Lookup

GHSA-7J8X-2FGW-FVX8

Vulnerability from github – Published: 2026-10-23 15:31 – Updated: 2026-10-24 15:32

Details

In the Linux kernel, the following vulnerability has been resolved:

drm/xe: Fix stale pinned_link entry when fb-pin performs the final unpin

xe_bo_pin_external() and xe_bo_unpin_external() maintain the bo's pinned_link list membership in xe->pinned.late.external, based on whether the current call is the outermost pin or the final unpin. However, the same external bo's pin_count can also be raised and lowered directly by __xe_pin_fb_vma()/__xe_unpin_fb_vma(), which pin the bo as a display scanout buffer without going through xe_bo_pin_external()/xe_bo_unpin_external() at all, and have no notion of, or ownership over, pinned_link.

If a bo is pinned both externally (e.g. dma-buf export) and as an fb, and the external unpin happens first, xe_bo_unpin_external() correctly observes pin_count > 1 and leaves the bo on pinned_link. When the fb unpin later performs the true last unpin (pin_count 1 -> 0), it never touches pinned_link, leaving the bo linked on xe->pinned.late.external indefinitely. Once the bo is subsequently freed, this stale list entry points into freed memory, corrupting the list and risking a use-after-free the next time the list is walked or spliced.

The backup object pin/unpin sites in xe_bo_notifier_prepare_pinned()/ xe_bo_notifier_unprepare_pinned() have the same bypass characteristic, though they never add their bo to a pinned list, so are not affected by this particular list-corruption issue.

Move the pinned_link removal into xe_bo_account_unpin(), which already runs on every unpin path (kernel, external, framebuffer, backup object) right before the true 1 -> 0 pin_count transition. Since list_del_init() only operates on the node itself, this removal is list-agnostic and safe to perform regardless of which list (external or kernel_bo_present) the bo happens to be linked on, or which code path is performing the final unpin. Drop the now-redundant explicit list_del_init() calls in xe_bo_unpin_external() and xe_bo_unpin().

v2: - New patch

v3: - Rebased on changes to previous patch.

(cherry picked from commit ca58d36a1f93af586ee93b340c9f9fd81312cc01)

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98999"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-23T13:17:22Z",
    "severity": "HIGH"
  },
  "details": "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\u0027s\npinned_link list membership in xe-\u003epinned.late.external, based on\nwhether the current call is the outermost pin or the final unpin.\nHowever, the same external bo\u0027s 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 \u003e 1 and leaves the bo on pinned_link. When the fb\nunpin later performs the true last unpin (pin_count 1 -\u003e 0), it never\ntouches pinned_link, leaving the bo linked on xe-\u003epinned.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 -\u003e 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)",
  "id": "GHSA-7j8x-2fgw-fvx8",
  "modified": "2026-10-24T15:32:49Z",
  "published": "2026-10-23T15:31:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98999"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3a11adcfd9a2de74d405bd3e8c4d7a1b328e4684"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b3eaff982839e5c22912d604cd8e7748cece8d63"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cf238c067eaae1cbfb00738e29219b9568d2313e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-98999 (GCVE-0-2026-98999)

Vulnerability from cvelistv5 – Published: 2026-10-23 12:20 – Updated: 2026-10-24 14:09

Title

drm/xe: Fix stale pinned_link entry when fb-pin performs the final unpin

Summary

In the Linux kernel, the following vulnerability has been resolved: drm/xe: Fix stale pinned_link entry when fb-pin performs the final unpin xe_bo_pin_external() and xe_bo_unpin_external() maintain the bo's pinned_link list membership in xe->pinned.late.external, based on whether the current call is the outermost pin or the final unpin. However, the same external bo's pin_count can also be raised and lowered directly by __xe_pin_fb_vma()/__xe_unpin_fb_vma(), which pin the bo as a display scanout buffer without going through xe_bo_pin_external()/xe_bo_unpin_external() at all, and have no notion of, or ownership over, pinned_link. If a bo is pinned both externally (e.g. dma-buf export) and as an fb, and the external unpin happens first, xe_bo_unpin_external() correctly observes pin_count > 1 and leaves the bo on pinned_link. When the fb unpin later performs the true last unpin (pin_count 1 -> 0), it never touches pinned_link, leaving the bo linked on xe->pinned.late.external indefinitely. Once the bo is subsequently freed, this stale list entry points into freed memory, corrupting the list and risking a use-after-free the next time the list is walked or spliced. The backup object pin/unpin sites in xe_bo_notifier_prepare_pinned()/ xe_bo_notifier_unprepare_pinned() have the same bypass characteristic, though they never add their bo to a pinned list, so are not affected by this particular list-corruption issue. Move the pinned_link removal into xe_bo_account_unpin(), which already runs on every unpin path (kernel, external, framebuffer, backup object) right before the true 1 -> 0 pin_count transition. Since list_del_init() only operates on the node itself, this removal is list-agnostic and safe to perform regardless of which list (external or kernel_bo_present) the bo happens to be linked on, or which code path is performing the final unpin. Drop the now-redundant explicit list_del_init() calls in xe_bo_unpin_external() and xe_bo_unpin(). v2: - New patch v3: - Rebased on changes to previous patch. (cherry picked from commit ca58d36a1f93af586ee93b340c9f9fd81312cc01)

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7056 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/3a11adcfd9a2de74d…
https://git.kernel.org/stable/c/b3eaff982839e5c22…
https://git.kernel.org/stable/c/cf238c067eaae1cbf…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 44e694958b95395bd1c41508c88c8ca141bf9bd7 , < 3a11adcfd9a2de74d405bd3e8c4d7a1b328e4684 (git) Affected: 44e694958b95395bd1c41508c88c8ca141bf9bd7 , < b3eaff982839e5c22912d604cd8e7748cece8d63 (git) Affected: 44e694958b95395bd1c41508c88c8ca141bf9bd7 , < cf238c067eaae1cbfb00738e29219b9568d2313e (git)
Linux	Linux	Affected: 6.8 Unaffected: 0 , < 6.8 (semver) Unaffected: 6.18.57 , ≤ 6.18.* (semver) Unaffected: 7.2.11 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/xe/xe_bo.c"
          ],
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          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3a11adcfd9a2de74d405bd3e8c4d7a1b328e4684",
              "status": "affected",
              "version": "44e694958b95395bd1c41508c88c8ca141bf9bd7",
              "versionType": "git"
            },
            {
              "lessThan": "b3eaff982839e5c22912d604cd8e7748cece8d63",
              "status": "affected",
              "version": "44e694958b95395bd1c41508c88c8ca141bf9bd7",
              "versionType": "git"
            },
            {
              "lessThan": "cf238c067eaae1cbfb00738e29219b9568d2313e",
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              "version": "44e694958b95395bd1c41508c88c8ca141bf9bd7",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/xe/xe_bo.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.8"
            },
            {
              "lessThan": "6.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.57",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.57",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.11",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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\u0027s\npinned_link list membership in xe-\u003epinned.late.external, based on\nwhether the current call is the outermost pin or the final unpin.\nHowever, the same external bo\u0027s 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 \u003e 1 and leaves the bo on pinned_link. When the fb\nunpin later performs the true last unpin (pin_count 1 -\u003e 0), it never\ntouches pinned_link, leaving the bo linked on xe-\u003epinned.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 -\u003e 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": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Local DRM ioctls reach patched xe_bo_account_unpin(): DRM_IOCTL_MODE_ATOMIC -\u003e intel_atomic_commit -\u003e intel_cleanup_plane_fb -\u003e __xe_unpin_fb_vma -\u003e xe_bo_unpin_account -\u003e 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-\u003epinned.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-\u003epinned.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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-24T14:09:56.167Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3a11adcfd9a2de74d405bd3e8c4d7a1b328e4684"
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        {
          "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"
      }
    }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98999",
    "datePublished": "2026-10-23T12:20:19.451Z",
    "dateReserved": "2026-09-25T10:25:14.385Z",
    "dateUpdated": "2026-10-24T14:09:56.167Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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