GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2026-89755 (GCVE-0-2026-89755)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:46 – Updated: 2026-09-13 06:34
VLAI
Title
mm/migrate_device: clear stale mapping after freeing swapcache
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/migrate_device: clear stale mapping after freeing swapcache __migrate_device_pages() reads the folio mapping before calling folio_free_swap(). When folio_free_swap() succeeds, the folio is removed from the swap cache, but the saved mapping still points to swap_space. Passing the stale mapping to folio_migrate_mapping() makes it use the mapped-folio path for a folio that is no longer in swapcache. It can then operate on swap_space.i_pages with invalid reference accounting, eventually triggering a folio reference count BUG. After a successful split, nr still contains the number of pages in the original large folio, although each resulting page is now a separate order-0 folio. Reset nr to 1 so each split folio is processed separately, including its own swapcache removal and mapping lookup. Refresh the saved mapping after folio_free_swap() so the current folio state is used during migration.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: df263d9a7dffee94ca5391120ee3b0587efa07f1 , < 8ffedc6573a665cdc31ebe47eae7b32b78d0df83 (git)
Affected: df263d9a7dffee94ca5391120ee3b0587efa07f1 , < 34a00895d032a414830d41106a09329ae6c251b6 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.6
Unaffected: 0 , < 6.6 (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/migrate_device.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8ffedc6573a665cdc31ebe47eae7b32b78d0df83",
              "status": "affected",
              "version": "df263d9a7dffee94ca5391120ee3b0587efa07f1",
              "versionType": "git"
            },
            {
              "lessThan": "34a00895d032a414830d41106a09329ae6c251b6",
              "status": "affected",
              "version": "df263d9a7dffee94ca5391120ee3b0587efa07f1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/migrate_device.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.6"
            },
            {
              "lessThan": "6.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/migrate_device: clear stale mapping after freeing swapcache\n\n__migrate_device_pages() reads the folio mapping before calling\nfolio_free_swap().  When folio_free_swap() succeeds, the folio is removed\nfrom the swap cache, but the saved mapping still points to swap_space.\n\nPassing the stale mapping to folio_migrate_mapping() makes it use the\nmapped-folio path for a folio that is no longer in swapcache.  It can then\noperate on swap_space.i_pages with invalid reference accounting,\neventually triggering a folio reference count BUG.\n\nAfter a successful split, nr still contains the number of pages in the\noriginal large folio, although each resulting page is now a separate\norder-0 folio.  Reset nr to 1 so each split folio is processed separately,\nincluding its own swapcache removal and mapping lookup.\n\nRefresh the saved mapping after folio_free_swap() so the current folio\nstate is used during migration."
        }
      ],
      "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",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is in __migrate_device_pages() on the migrate-to-device path (migrate_vma_pages), reached from local GPU HMM/SVM ioctls such as AMDKFD_IOC_SVM, DRM_NOUVEAU_SVM_BIND (DRM_RENDER_ALLOW), and Intel Xe drm_pagemap_migrate_to_devmem, not from network packets.\nAC:L - The attacker controls both preconditions: anonymous pages in their VMA, optionally kept in swapcache via pageout/swapin, then a migrate-to-VRAM ioctl. folio_free_swap() succeeds on locked mapped swapcache folios with swap count 0, which the attacker can arrange; no victim timing or uncontrollable layout is required.\nPR:L - Nouveau SVM bind is DRM_RENDER_ALLOW and KFD SVM/Xe pagemap paths have no capable() or DRM-master check. An unprivileged local user with typical render/video-group access to /dev/dri/renderD* or /dev/kfd on GPU systems can trigger the migration.\nUI:N - The attacker drives the whole sequence in their own process (anonymous mmap, optional madvise pageout, and GPU SVM migrate-to-device ioctls). No action by another user or administrator is required.\nS:U - Impact is host-kernel swap-cache and folio-refcount corruption, i.e. standard local privilege escalation in the same security authority, not a KVM/Xen guest-to-host escape or IOMMU/DMA boundary bypass.\nC:H - After folio_free_swap() the stale mapping still points at swap_space, so folio_migrate_mapping() xas_store()s a device-private folio into the global swap cache and underflows the source refcount; that UAF/type confusion of swap_space.i_pages yields an arbitrary kernel read primitive.\nI:H - The same xarray insertion and refcount underflow corrupt shared MM metadata (swap cache and folio references), which is exploitable for heap reuse and arbitrary kernel writes or control-flow hijack, not a bounded integrity change.\nA:H - Invalid reference accounting on swap_space.i_pages is documented to hit a folio reference-count BUG, and the resulting underflow/UAF also causes kernel oops or panic even without a completed exploit."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:34:01.430Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/8ffedc6573a665cdc31ebe47eae7b32b78d0df83"
        },
        {
          "url": "https://git.kernel.org/stable/c/34a00895d032a414830d41106a09329ae6c251b6"
        }
      ],
      "title": "mm/migrate_device: clear stale mapping after freeing swapcache",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89755",
    "datePublished": "2026-09-11T19:46:58.295Z",
    "dateReserved": "2026-09-11T19:38:34.763Z",
    "dateUpdated": "2026-09-13T06:34:01.430Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-89755",
      "date": "2026-09-16",
      "epss": "0.00143",
      "percentile": "0.04002"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-14T14:49:20.000Z",
      "cve": "CVE-2026-89755",
      "id": "msrc_CVE-2026-89755",
      "initial_release_date": "2026-09-13T01:03:36.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "mm/migrate_device: clear stale mapping after freeing swapcache",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89755.json",
      "version": "2"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-89755\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-09-11T20:20:06.533\",\"lastModified\":\"2026-09-13T07:17:39.983\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmm/migrate_device: clear stale mapping after freeing swapcache\\n\\n__migrate_device_pages() reads the folio mapping before calling\\nfolio_free_swap().  When folio_free_swap() succeeds, the folio is removed\\nfrom the swap cache, but the saved mapping still points to swap_space.\\n\\nPassing the stale mapping to folio_migrate_mapping() makes it use the\\nmapped-folio path for a folio that is no longer in swapcache.  It can then\\noperate on swap_space.i_pages with invalid reference accounting,\\neventually triggering a folio reference count BUG.\\n\\nAfter a successful split, nr still contains the number of pages in the\\noriginal large folio, although each resulting page is now a separate\\norder-0 folio.  Reset nr to 1 so each split folio is processed separately,\\nincluding its own swapcache removal and mapping lookup.\\n\\nRefresh the saved mapping after folio_free_swap() so the current folio\\nstate is used during migration.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"mm/migrate_device.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"df263d9a7dffee94ca5391120ee3b0587efa07f1\",\"lessThan\":\"8ffedc6573a665cdc31ebe47eae7b32b78d0df83\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"df263d9a7dffee94ca5391120ee3b0587efa07f1\",\"lessThan\":\"34a00895d032a414830d41106a09329ae6c251b6\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"mm/migrate_device.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.6\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.6\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.4\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"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}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/34a00895d032a414830d41106a09329ae6c251b6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8ffedc6573a665cdc31ebe47eae7b32b78d0df83\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-13T06:52:44+00:00",
      "cve": "CVE-2026-89755",
      "id": "CVE-2026-89755",
      "initial_release_date": "2026-09-11T19:46:58.295000+00:00",
      "product_status:known_affected": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel: System crash due to stale memory mapping in device migration",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89755.json",
      "version": "3"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.