{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89755", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.763Z", "datePublished": "2026-09-11T19:46:58.295Z", "dateUpdated": "2026-10-19T08:52:08.943Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:52:08.943Z" }, "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": { "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 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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/migrate_device.c" ], "versions": [ { "version": "df263d9a7dffee94ca5391120ee3b0587efa07f1", "lessThan": "4fa91f7bbc4135240b67daac03fc17d9e180a331", "status": "affected", "versionType": "git" }, { "version": "df263d9a7dffee94ca5391120ee3b0587efa07f1", "lessThan": "8ffedc6573a665cdc31ebe47eae7b32b78d0df83", "status": "affected", "versionType": "git" }, { "version": "df263d9a7dffee94ca5391120ee3b0587efa07f1", "lessThan": "34a00895d032a414830d41106a09329ae6c251b6", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/migrate_device.c" ], "versions": [ { "version": "6.6", "status": "affected" }, { "version": "0", "lessThan": "6.6", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.111", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "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": "6.6", "versionEndExcluding": "6.12.111" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "7.2.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/4fa91f7bbc4135240b67daac03fc17d9e180a331" }, { "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" } } } }