{"id":"CVE-2025-39961","revision":"e9f3f9a72243460bbd3c0c406cbd7ffc","records":[{"revision":"e9f3f9a72243460bbd3c0c406cbd7ffc","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2025-39961","aliases":[],"title":"iommu/amd/pgtbl: Fix possible race while increase page table level","description":"In the Linux kernel, the following vulnerability has been resolved:\n\niommu/amd/pgtbl: Fix possible race while increase page table level\n\nThe AMD IOMMU host page table implementation supports dynamic page table levels\n(up to 6 levels), starting with a 3-level configuration that expands based on\nIOVA address. The kernel maintains a root pointer and current page table level\nto enable proper page table walks in alloc_pte()/fetch_pte() operations.\n\nThe IOMMU IOVA allocator initially starts with 32-bit address and onces its\nexhuasted it switches to 64-bit address (max address is determined based\non IOMMU and device DMA capability). To support larger IOVA, AMD IOMMU\ndriver increases page table level.\n\nBut in unmap path (iommu_v1_unmap_pages()), fetch_pte() reads\npgtable->[root/mode] without lock. So its possible that in exteme corner case,\nwhen increase_address_space() is updating pgtable->[root/mode], fetch_pte()\nreads wrong page table level (pgtable->mode). It does compare the value with\nlevel encoded in page table and returns NULL. This will result is\niommu_unmap ops to fail and upper layer may retry/log WARN_ON.\n\nCPU 0 CPU 1\n------ ------\nmap pages unmap pages\nalloc_pte() -> increase_address_space() iommu_v1_unmap_pages() -> fetch_pte()\n pgtable->root = pte (new root value)\n READ pgtable->[mode/root]\n\t\t\t\t\t Reads new root, old mode\n Updates mode (pgtable->mode += 1)\n\nSince Page table level updates are infrequent and already synchronized with a\nspinlock, implement seqcount to enable lock-free read operations on the read path.","state":0,"publishedAt":"2025-10-09T12:13:22.029+00:00","modifiedAt":"2026-10-15T22:02:34.065+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"drivers/iommu/amd/amd_iommu_types.h\",\n \"drivers/iommu/amd/io_pgtable.c\"\n ],\n \"versions\": [\n {\n \"version\": \"754265bcab78a9014f0f99cd35e0d610fcd7dfa7\",\n \"lessThan\": \"075abf0b1a958acfbea2435003d228e738e90346\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"754265bcab78a9014f0f99cd35e0d610fcd7dfa7\",\n \"lessThan\": \"cd92c8ab336c3a633d46e6f35ebcd3509ae7db3b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"754265bcab78a9014f0f99cd35e0d610fcd7dfa7\",\n \"lessThan\": \"7d462bdecb7d9c32934dab44aaeb7ea7d73a27a2\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"754265bcab78a9014f0f99cd35e0d610fcd7dfa7\",\n \"lessThan\": \"1e56310b40fd2e7e0b9493da9ff488af145bdd0c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"6fb92f18555a7b8e085267d513612dc0ff9a5360\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"b15bf74405faa1a65025eb8a6eb337e140e5250a\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0d50f7b1e8c80a8c20db5049e269468c059b0378\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"785ca708a908b9c596ede852470ba28b8dc3e40b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"4.9.194\",\n \"lessThan\": \"4.10\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.14.146\",\n \"lessThan\": \"4.15\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.19.75\",\n \"lessThan\": \"4.20\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.2.17\",\n \"lessThan\": \"5.3\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"drivers/iommu/amd/amd_iommu_types.h\",\n \"drivers/iommu/amd/io_pgtable.c\"\n ],\n \"versions\": [\n {\n \"version\": \"5.3\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"5.3\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.108\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.49\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.16.9\",\n \"lessThanOrEqual\": \"6.16.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.17\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","score":8.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/075abf0b1a958acfbea2435003d228e738e90346","https://git.kernel.org/stable/c/cd92c8ab336c3a633d46e6f35ebcd3509ae7db3b","https://git.kernel.org/stable/c/7d462bdecb7d9c32934dab44aaeb7ea7d73a27a2","https://git.kernel.org/stable/c/1e56310b40fd2e7e0b9493da9ff488af145bdd0c"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-39961","license":"CVE Program Terms of Use","key":"cve-program:CVE-2025-39961","identifiers":["CVE-2025-39961"]},"retained":false,"historicalAffected":[]}],"coverage":[]}