{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-46280", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-13T15:03:33.110Z", "datePublished": "2026-06-08T15:41:23.095Z", "dateUpdated": "2026-08-05T12:31:01.052Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:31:01.052Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nlib: test_hmm: evict device pages on file close to avoid use-after-free\n\nPatch series \"Minor hmm_test fixes and cleanups\".\n\nTwo bugfixes a cleanup for the HMM kernel selftests. These were mostly\nreported by Zenghui Yu with special thanks to Lorenzo for analysing and\npointing out the problems.\n\n\nThis patch (of 3):\n\nWhen dmirror_fops_release() is called it frees the dmirror struct but\ndoesn't migrate device private pages back to system memory first. This\nleaves those pages with a dangling zone_device_data pointer to the freed\ndmirror.\n\nIf a subsequent fault occurs on those pages (eg. during coredump) the\ndmirror_devmem_fault() callback dereferences the stale pointer causing a\nkernel panic. This was reported [1] when running mm/ksft_hmm.sh on arm64,\nwhere a test failure triggered SIGABRT and the resulting coredump walked\nthe VMAs faulting in the stale device private pages.\n\nFix this by calling dmirror_device_evict_chunk() for each devmem chunk in\ndmirror_fops_release() to migrate all device private pages back to system\nmemory before freeing the dmirror struct. The function is moved earlier\nin the file to avoid a forward declaration." } ], "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 - Exploitation requires local syscalls to open the hmm_dmirror character device, issue HMM_DMIRROR_MIGRATE_TO_DEV ioctl, close the fd, and fault migrated pages; there is no network, adjacent-wireless, or physical-device attack path.\nAC:L - The UAF is deterministically triggered by the attacker's own migrate-then-close-then-fault sequence with no race or external timing dependency; the attacker fully controls both sides of the lifecycle.\nPR:L - The vulnerable ioctl and release paths perform no capability or permission checks beyond opening the local character device; any local user who can access /dev/hmm_dmirrorN can execute the full exploit chain without real root privileges in the init namespace.\nUI:N - No victim interaction is required; the attacker triggers the fault themselves by accessing their own migrated pages or aborting for coredump after closing the device file.\nS:U - Impact is confined to kernel memory corruption and panic within the same kernel security boundary; this is a test-module UAF, not a VM escape, IOMMU bypass, or cross-authority sandbox breakout.\nC:H - The stale dmirror pointer is dereferenced in dmirror_devmem_fault() to read freed kmalloc memory (dmirror->mdevice, dmirror->flags), giving a classic UAF information-disclosure primitive.\nI:H - The fault handler continues to use the freed dmirror for migration and xa_erase on dmirror->pt, enabling heap reuse attacks and arbitrary kernel memory write or code-execution primitives.\nA:H - The bug was reported to cause kernel panic during coredump VMA walks, and any UAF page fault on stale device-private pages can oops or panic the system." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "lib/test_hmm.c" ], "versions": [ { "version": "b2ef9f5a5cb37643ca5def3516c546457074b882", "lessThan": "234071b4318feaeb27cd2e4e1b16ef6b055adf89", "status": "affected", "versionType": "git" }, { "version": "b2ef9f5a5cb37643ca5def3516c546457074b882", "lessThan": "bf477abd448c76bb8ea51c9b4f63a3a17c4b6239", "status": "affected", "versionType": "git" }, { "version": "b2ef9f5a5cb37643ca5def3516c546457074b882", "lessThan": "5846715b6382dd4c6a69b35a56ca6115d33bc2a0", "status": "affected", "versionType": "git" }, { "version": "b2ef9f5a5cb37643ca5def3516c546457074b882", "lessThan": "38f113f81d3f0adc658a4475dd3ecaec985e21d3", "status": "affected", "versionType": "git" }, { "version": "b2ef9f5a5cb37643ca5def3516c546457074b882", "lessThan": "9de1eb0aac2862d6144b8db0ec1388e79f8bc3e1", "status": "affected", "versionType": "git" }, { "version": "b2ef9f5a5cb37643ca5def3516c546457074b882", "lessThan": "744dd97752ef1076a8d8672bb0d8aa2c7abc1144", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "lib/test_hmm.c" ], "versions": [ { "version": "5.8", "status": "affected" }, { "version": "0", "lessThan": "5.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.176", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.140", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.86", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.27", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.4", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "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": "5.8", "versionEndExcluding": "6.1.176" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.6.140" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.12.86" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "6.18.27" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "7.0.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.8", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/234071b4318feaeb27cd2e4e1b16ef6b055adf89" }, { "url": "https://git.kernel.org/stable/c/bf477abd448c76bb8ea51c9b4f63a3a17c4b6239" }, { "url": "https://git.kernel.org/stable/c/5846715b6382dd4c6a69b35a56ca6115d33bc2a0" }, { "url": "https://git.kernel.org/stable/c/38f113f81d3f0adc658a4475dd3ecaec985e21d3" }, { "url": "https://git.kernel.org/stable/c/9de1eb0aac2862d6144b8db0ec1388e79f8bc3e1" }, { "url": "https://git.kernel.org/stable/c/744dd97752ef1076a8d8672bb0d8aa2c7abc1144" } ], "title": "lib: test_hmm: evict device pages on file close to avoid use-after-free", "x_generator": { "engine": "bippy-1.2.0" } } } }