CVE-2025-39961 (GCVE-0-2025-39961)

Vulnerability from cvelistv5 – Published: 2025-10-09 12:13 – Updated: 2025-10-09 12:13
VLAI?
Title
iommu/amd/pgtbl: Fix possible race while increase page table level
Summary
In the Linux kernel, the following vulnerability has been resolved: iommu/amd/pgtbl: Fix possible race while increase page table level The AMD IOMMU host page table implementation supports dynamic page table levels (up to 6 levels), starting with a 3-level configuration that expands based on IOVA address. The kernel maintains a root pointer and current page table level to enable proper page table walks in alloc_pte()/fetch_pte() operations. The IOMMU IOVA allocator initially starts with 32-bit address and onces its exhuasted it switches to 64-bit address (max address is determined based on IOMMU and device DMA capability). To support larger IOVA, AMD IOMMU driver increases page table level. But in unmap path (iommu_v1_unmap_pages()), fetch_pte() reads pgtable->[root/mode] without lock. So its possible that in exteme corner case, when increase_address_space() is updating pgtable->[root/mode], fetch_pte() reads wrong page table level (pgtable->mode). It does compare the value with level encoded in page table and returns NULL. This will result is iommu_unmap ops to fail and upper layer may retry/log WARN_ON. CPU 0 CPU 1 ------ ------ map pages unmap pages alloc_pte() -> increase_address_space() iommu_v1_unmap_pages() -> fetch_pte() pgtable->root = pte (new root value) READ pgtable->[mode/root] Reads new root, old mode Updates mode (pgtable->mode += 1) Since Page table level updates are infrequent and already synchronized with a spinlock, implement seqcount to enable lock-free read operations on the read path.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 754265bcab78a9014f0f99cd35e0d610fcd7dfa7 , < 075abf0b1a958acfbea2435003d228e738e90346 (git)
Affected: 754265bcab78a9014f0f99cd35e0d610fcd7dfa7 , < cd92c8ab336c3a633d46e6f35ebcd3509ae7db3b (git)
Affected: 754265bcab78a9014f0f99cd35e0d610fcd7dfa7 , < 7d462bdecb7d9c32934dab44aaeb7ea7d73a27a2 (git)
Affected: 754265bcab78a9014f0f99cd35e0d610fcd7dfa7 , < 1e56310b40fd2e7e0b9493da9ff488af145bdd0c (git)
Affected: 6fb92f18555a7b8e085267d513612dc0ff9a5360 (git)
Affected: b15bf74405faa1a65025eb8a6eb337e140e5250a (git)
Affected: 0d50f7b1e8c80a8c20db5049e269468c059b0378 (git)
Affected: 785ca708a908b9c596ede852470ba28b8dc3e40b (git)
Create a notification for this product.
    Linux Linux Affected: 5.3
Unaffected: 0 , < 5.3 (semver)
Unaffected: 6.6.108 , ≤ 6.6.* (semver)
Unaffected: 6.12.49 , ≤ 6.12.* (semver)
Unaffected: 6.16.9 , ≤ 6.16.* (semver)
Unaffected: 6.17 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/amd/amd_iommu_types.h",
            "drivers/iommu/amd/io_pgtable.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "075abf0b1a958acfbea2435003d228e738e90346",
              "status": "affected",
              "version": "754265bcab78a9014f0f99cd35e0d610fcd7dfa7",
              "versionType": "git"
            },
            {
              "lessThan": "cd92c8ab336c3a633d46e6f35ebcd3509ae7db3b",
              "status": "affected",
              "version": "754265bcab78a9014f0f99cd35e0d610fcd7dfa7",
              "versionType": "git"
            },
            {
              "lessThan": "7d462bdecb7d9c32934dab44aaeb7ea7d73a27a2",
              "status": "affected",
              "version": "754265bcab78a9014f0f99cd35e0d610fcd7dfa7",
              "versionType": "git"
            },
            {
              "lessThan": "1e56310b40fd2e7e0b9493da9ff488af145bdd0c",
              "status": "affected",
              "version": "754265bcab78a9014f0f99cd35e0d610fcd7dfa7",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6fb92f18555a7b8e085267d513612dc0ff9a5360",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b15bf74405faa1a65025eb8a6eb337e140e5250a",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "0d50f7b1e8c80a8c20db5049e269468c059b0378",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "785ca708a908b9c596ede852470ba28b8dc3e40b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/amd/amd_iommu_types.h",
            "drivers/iommu/amd/io_pgtable.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.3"
            },
            {
              "lessThan": "5.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.108",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.49",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.16.*",
              "status": "unaffected",
              "version": "6.16.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.17",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.108",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.49",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16.9",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.9.194",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.14.146",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.19.75",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "5.2.17",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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-\u003e[root/mode] without lock. So its possible that in exteme corner case,\nwhen increase_address_space() is updating pgtable-\u003e[root/mode], fetch_pte()\nreads wrong page table level (pgtable-\u003emode). 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() -\u003e increase_address_space()      iommu_v1_unmap_pages() -\u003e fetch_pte()\n  pgtable-\u003eroot = pte (new root value)\n                                             READ pgtable-\u003e[mode/root]\n\t\t\t\t\t       Reads new root, old mode\n  Updates mode (pgtable-\u003emode += 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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-10-09T12:13:22.029Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/075abf0b1a958acfbea2435003d228e738e90346"
        },
        {
          "url": "https://git.kernel.org/stable/c/cd92c8ab336c3a633d46e6f35ebcd3509ae7db3b"
        },
        {
          "url": "https://git.kernel.org/stable/c/7d462bdecb7d9c32934dab44aaeb7ea7d73a27a2"
        },
        {
          "url": "https://git.kernel.org/stable/c/1e56310b40fd2e7e0b9493da9ff488af145bdd0c"
        }
      ],
      "title": "iommu/amd/pgtbl: Fix possible race while increase page table level",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-39961",
    "datePublished": "2025-10-09T12:13:22.029Z",
    "dateReserved": "2025-04-16T07:20:57.149Z",
    "dateUpdated": "2025-10-09T12:13:22.029Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-39961\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-10-09T13:15:32.250\",\"lastModified\":\"2025-10-09T15:50:04.013\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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-\u003e[root/mode] without lock. So its possible that in exteme corner case,\\nwhen increase_address_space() is updating pgtable-\u003e[root/mode], fetch_pte()\\nreads wrong page table level (pgtable-\u003emode). 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() -\u003e increase_address_space()      iommu_v1_unmap_pages() -\u003e fetch_pte()\\n  pgtable-\u003eroot = pte (new root value)\\n                                             READ pgtable-\u003e[mode/root]\\n\\t\\t\\t\\t\\t       Reads new root, old mode\\n  Updates mode (pgtable-\u003emode += 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.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/075abf0b1a958acfbea2435003d228e738e90346\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/1e56310b40fd2e7e0b9493da9ff488af145bdd0c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7d462bdecb7d9c32934dab44aaeb7ea7d73a27a2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cd92c8ab336c3a633d46e6f35ebcd3509ae7db3b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

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.