{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72172", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.910Z", "datePublished": "2026-08-15T05:53:37.795Z", "dateUpdated": "2026-08-23T12:47:00.343Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-23T12:47:00.343Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/mm_init: fix uninitialized struct pages for ZONE_DEVICE\n\nIf DAX memory is hotplugged into an unoccupied subsection of an early\nsection, section_activate() reuses the unoptimized boot memmap. However,\ncompound_nr_pages() still assumes that vmemmap optimization is in effect\nand initializes only the reduced number of struct pages. As a result, the\nremaining tail struct pages are left uninitialized, which can later lead\nto unexpected behavior or crashes.\n\nFix this by treating early sections as unoptimized when calculating how\nmany struct pages to initialize." } ], "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 flaw is in memmap_init_zone_device() reached via memremap_pages()/devm_memremap_pages() during device-DAX driver probe or ZONE_DEVICE hotplug (e.g., dev_dax_probe, Hyper-V VTL), not via network protocols; subsequent impact is triggered by local mmap/page-fault/get_user_pages activity on the DAX device.\nAC:L - After device-DAX with compound vmemmap (vmemmap_shift>0) is hotplugged into an unoccupied early-section subsection, uninitialized tail struct pages remain indefinitely; an attacker only needs to access that memory (e.g., mmap /dev/dax) to invoke kernel page-metadata operations, without races or uncontrollable victim state.\nPR:L - While initial ZONE_DEVICE hotplug requires administrator device-DAX configuration (daxctl/ndctl, driver bind), on a configured persistent-memory or cloud server unprivileged local users with /dev/dax access can trigger kernel use of the corrupt struct pages via mmap and page faults without CAP_SYS_ADMIN in the init namespace.\nUI:N - Exploitation requires no victim interaction beyond the attacker (or any local user) running programs that mmap or access the already-provisioned DAX device; no mount, click, or plug/unplug action by another user is needed at exploit time.\nS:U - Impact is kernel memory corruption, information disclosure, and denial of service within the host kernel security boundary; it does not inherently cross VM/host, IOMMU, or sandbox isolation even though cloud persistent-memory deployments are a plausible high-impact scenario.\nC:H - Uninitialized tail struct page metadata (flags, refcount, pgmap/lru fields) is later interpreted as valid by the MM subsystem; garbage contents can be read through page-table walks, refcount checks, and folio lookups, yielding kernel memory disclosure comparable to other uninitialized-page corruption bugs.\nI:H - Corrupt struct page fields can drive incorrect refcounting, compound-head/tail linkage, and ZONE_DEVICE pgmap handling, enabling heap-style memory corruption and potential arbitrary kernel write or control-flow hijack, not merely bounded data modification.\nA:H - The fix commit and call path explicitly warn of unexpected behavior and crashes; operations on uninitialized struct pages can provoke kernel oops, BUG_ON, use-after-free, or panic during page allocation, migration, or DAX fault handling, giving reliable denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "mm/mm_init.c" ], "versions": [ { "version": "6fd3620b342861de9547ea01d28f664892ef51a1", "lessThan": "c5ef574d57e4a701485c13f26822328c91f05413", "status": "affected", "versionType": "git" }, { "version": "6fd3620b342861de9547ea01d28f664892ef51a1", "lessThan": "511a60e71aec308b24722cffc1912bf6befb87bf", "status": "affected", "versionType": "git" }, { "version": "6fd3620b342861de9547ea01d28f664892ef51a1", "lessThan": "11f2826e9ee6f24aaa774e3dcd75abbe4b3091b6", "status": "affected", "versionType": "git" }, { "version": "6fd3620b342861de9547ea01d28f664892ef51a1", "lessThan": "da5234df0941665f3a3f5b80f3dab94046537be0", "status": "affected", "versionType": "git" }, { "version": "6fd3620b342861de9547ea01d28f664892ef51a1", "lessThan": "b91e27bce37cab9f35de0059278ebe457ca9878b", "status": "affected", "versionType": "git" }, { "version": "6fd3620b342861de9547ea01d28f664892ef51a1", "lessThan": "cd681403a87085562499d60325b7b45d3be11217", "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/mm_init.c" ], "versions": [ { "version": "5.19", "status": "affected" }, { "version": "0", "lessThan": "5.19", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.184", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "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": "5.19", "versionEndExcluding": "6.1.184" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/c5ef574d57e4a701485c13f26822328c91f05413" }, { "url": "https://git.kernel.org/stable/c/511a60e71aec308b24722cffc1912bf6befb87bf" }, { "url": "https://git.kernel.org/stable/c/11f2826e9ee6f24aaa774e3dcd75abbe4b3091b6" }, { "url": "https://git.kernel.org/stable/c/da5234df0941665f3a3f5b80f3dab94046537be0" }, { "url": "https://git.kernel.org/stable/c/b91e27bce37cab9f35de0059278ebe457ca9878b" }, { "url": "https://git.kernel.org/stable/c/cd681403a87085562499d60325b7b45d3be11217" } ], "title": "mm/mm_init: fix uninitialized struct pages for ZONE_DEVICE", "x_generator": { "engine": "bippy-1.2.0" } } } }