CVE-2026-31466 (GCVE-0-2026-31466)

Vulnerability from cvelistv5 – Published: 2026-04-22 13:53 – Updated: 2026-05-11 22:09
VLAI?
Title
mm/huge_memory: fix folio isn't locked in softleaf_to_folio()
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/huge_memory: fix folio isn't locked in softleaf_to_folio() On arm64 server, we found folio that get from migration entry isn't locked in softleaf_to_folio(). This issue triggers when mTHP splitting and zap_nonpresent_ptes() races, and the root cause is lack of memory barrier in softleaf_to_folio(). The race is as follows: CPU0 CPU1 deferred_split_scan() zap_nonpresent_ptes() lock folio split_folio() unmap_folio() change ptes to migration entries __split_folio_to_order() softleaf_to_folio() set flags(including PG_locked) for tail pages folio = pfn_folio(softleaf_to_pfn(entry)) smp_wmb() VM_WARN_ON_ONCE(!folio_test_locked(folio)) prep_compound_page() for tail pages In __split_folio_to_order(), smp_wmb() guarantees page flags of tail pages are visible before the tail page becomes non-compound. smp_wmb() should be paired with smp_rmb() in softleaf_to_folio(), which is missed. As a result, if zap_nonpresent_ptes() accesses migration entry that stores tail pfn, softleaf_to_folio() may see the updated compound_head of tail page before page->flags. This issue will trigger VM_WARN_ON_ONCE() in pfn_swap_entry_folio() because of the race between folio split and zap_nonpresent_ptes() leading to a folio incorrectly undergoing modification without a folio lock being held. This is a BUG_ON() before commit 93976a20345b ("mm: eliminate further swapops predicates"), which in merged in v6.19-rc1. To fix it, add missing smp_rmb() if the softleaf entry is migration entry in softleaf_to_folio() and softleaf_to_page(). [tujinjiang@huawei.com: update function name and comments]
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: e9b61f19858a5d6c42ce2298cf138279375d0d9b , < 426ee10711586617da869c8bb798214965337617 (git)
Affected: e9b61f19858a5d6c42ce2298cf138279375d0d9b , < f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd (git)
Affected: e9b61f19858a5d6c42ce2298cf138279375d0d9b , < 722cfaf6b31d31123439e67b5deac6b1261a3dea (git)
Affected: e9b61f19858a5d6c42ce2298cf138279375d0d9b , < 7ddcf4a245c1c5a91fdd9698757e3d95179ffe41 (git)
Affected: e9b61f19858a5d6c42ce2298cf138279375d0d9b , < b8c49ad888892ad7b77062b9c102b799a3e9b4f8 (git)
Affected: e9b61f19858a5d6c42ce2298cf138279375d0d9b , < 7ad1997b9bc8032603df8f091761114479285769 (git)
Affected: e9b61f19858a5d6c42ce2298cf138279375d0d9b , < 8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7 (git)
Affected: e9b61f19858a5d6c42ce2298cf138279375d0d9b , < 4c5e7f0fcd592801c9cc18f29f80fbee84eb8669 (git)
Create a notification for this product.
Linux Linux Affected: 4.5
Unaffected: 0 , < 4.5 (semver)
Unaffected: 5.10.253 , ≤ 5.10.* (semver)
Unaffected: 5.15.203 , ≤ 5.15.* (semver)
Unaffected: 6.1.168 , ≤ 6.1.* (semver)
Unaffected: 6.6.134 , ≤ 6.6.* (semver)
Unaffected: 6.12.81 , ≤ 6.12.* (semver)
Unaffected: 6.18.21 , ≤ 6.18.* (semver)
Unaffected: 6.19.11 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (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": [
            "include/linux/leafops.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "426ee10711586617da869c8bb798214965337617",
              "status": "affected",
              "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
              "versionType": "git"
            },
            {
              "lessThan": "f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd",
              "status": "affected",
              "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
              "versionType": "git"
            },
            {
              "lessThan": "722cfaf6b31d31123439e67b5deac6b1261a3dea",
              "status": "affected",
              "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
              "versionType": "git"
            },
            {
              "lessThan": "7ddcf4a245c1c5a91fdd9698757e3d95179ffe41",
              "status": "affected",
              "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
              "versionType": "git"
            },
            {
              "lessThan": "b8c49ad888892ad7b77062b9c102b799a3e9b4f8",
              "status": "affected",
              "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
              "versionType": "git"
            },
            {
              "lessThan": "7ad1997b9bc8032603df8f091761114479285769",
              "status": "affected",
              "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
              "versionType": "git"
            },
            {
              "lessThan": "8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7",
              "status": "affected",
              "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
              "versionType": "git"
            },
            {
              "lessThan": "4c5e7f0fcd592801c9cc18f29f80fbee84eb8669",
              "status": "affected",
              "version": "e9b61f19858a5d6c42ce2298cf138279375d0d9b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/linux/leafops.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.5"
            },
            {
              "lessThan": "4.5",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.253",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.203",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.168",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.134",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.81",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.21",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.253",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.203",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.168",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.134",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.81",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.21",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.11",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/huge_memory: fix folio isn\u0027t locked in softleaf_to_folio()\n\nOn arm64 server, we found folio that get from migration entry isn\u0027t locked\nin softleaf_to_folio().  This issue triggers when mTHP splitting and\nzap_nonpresent_ptes() races, and the root cause is lack of memory barrier\nin softleaf_to_folio().  The race is as follows:\n\n\tCPU0                                             CPU1\n\ndeferred_split_scan()                              zap_nonpresent_ptes()\n  lock folio\n  split_folio()\n    unmap_folio()\n      change ptes to migration entries\n    __split_folio_to_order()                         softleaf_to_folio()\n      set flags(including PG_locked) for tail pages    folio = pfn_folio(softleaf_to_pfn(entry))\n      smp_wmb()                                        VM_WARN_ON_ONCE(!folio_test_locked(folio))\n      prep_compound_page() for tail pages\n\nIn __split_folio_to_order(), smp_wmb() guarantees page flags of tail pages\nare visible before the tail page becomes non-compound.  smp_wmb() should\nbe paired with smp_rmb() in softleaf_to_folio(), which is missed.  As a\nresult, if zap_nonpresent_ptes() accesses migration entry that stores tail\npfn, softleaf_to_folio() may see the updated compound_head of tail page\nbefore page-\u003eflags.\n\nThis issue will trigger VM_WARN_ON_ONCE() in pfn_swap_entry_folio()\nbecause of the race between folio split and zap_nonpresent_ptes()\nleading to a folio incorrectly undergoing modification without a folio\nlock being held.\n\nThis is a BUG_ON() before commit 93976a20345b (\"mm: eliminate further\nswapops predicates\"), which in merged in v6.19-rc1.\n\nTo fix it, add missing smp_rmb() if the softleaf entry is migration entry\nin softleaf_to_folio() and softleaf_to_page().\n\n[tujinjiang@huawei.com: update function name and comments]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:09:16.806Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/426ee10711586617da869c8bb798214965337617"
        },
        {
          "url": "https://git.kernel.org/stable/c/f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd"
        },
        {
          "url": "https://git.kernel.org/stable/c/722cfaf6b31d31123439e67b5deac6b1261a3dea"
        },
        {
          "url": "https://git.kernel.org/stable/c/7ddcf4a245c1c5a91fdd9698757e3d95179ffe41"
        },
        {
          "url": "https://git.kernel.org/stable/c/b8c49ad888892ad7b77062b9c102b799a3e9b4f8"
        },
        {
          "url": "https://git.kernel.org/stable/c/7ad1997b9bc8032603df8f091761114479285769"
        },
        {
          "url": "https://git.kernel.org/stable/c/8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7"
        },
        {
          "url": "https://git.kernel.org/stable/c/4c5e7f0fcd592801c9cc18f29f80fbee84eb8669"
        }
      ],
      "title": "mm/huge_memory: fix folio isn\u0027t locked in softleaf_to_folio()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31466",
    "datePublished": "2026-04-22T13:53:56.259Z",
    "dateReserved": "2026-03-09T15:48:24.097Z",
    "dateUpdated": "2026-05-11T22:09:16.806Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-31466",
      "date": "2026-05-23",
      "epss": "0.00012",
      "percentile": "0.01804"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-31466\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-04-22T14:16:42.780\",\"lastModified\":\"2026-05-07T18:25:42.033\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmm/huge_memory: fix folio isn\u0027t locked in softleaf_to_folio()\\n\\nOn arm64 server, we found folio that get from migration entry isn\u0027t locked\\nin softleaf_to_folio().  This issue triggers when mTHP splitting and\\nzap_nonpresent_ptes() races, and the root cause is lack of memory barrier\\nin softleaf_to_folio().  The race is as follows:\\n\\n\\tCPU0                                             CPU1\\n\\ndeferred_split_scan()                              zap_nonpresent_ptes()\\n  lock folio\\n  split_folio()\\n    unmap_folio()\\n      change ptes to migration entries\\n    __split_folio_to_order()                         softleaf_to_folio()\\n      set flags(including PG_locked) for tail pages    folio = pfn_folio(softleaf_to_pfn(entry))\\n      smp_wmb()                                        VM_WARN_ON_ONCE(!folio_test_locked(folio))\\n      prep_compound_page() for tail pages\\n\\nIn __split_folio_to_order(), smp_wmb() guarantees page flags of tail pages\\nare visible before the tail page becomes non-compound.  smp_wmb() should\\nbe paired with smp_rmb() in softleaf_to_folio(), which is missed.  As a\\nresult, if zap_nonpresent_ptes() accesses migration entry that stores tail\\npfn, softleaf_to_folio() may see the updated compound_head of tail page\\nbefore page-\u003eflags.\\n\\nThis issue will trigger VM_WARN_ON_ONCE() in pfn_swap_entry_folio()\\nbecause of the race between folio split and zap_nonpresent_ptes()\\nleading to a folio incorrectly undergoing modification without a folio\\nlock being held.\\n\\nThis is a BUG_ON() before commit 93976a20345b (\\\"mm: eliminate further\\nswapops predicates\\\"), which in merged in v6.19-rc1.\\n\\nTo fix it, add missing smp_rmb() if the softleaf entry is migration entry\\nin softleaf_to_folio() and softleaf_to_page().\\n\\n[tujinjiang@huawei.com: update function name and comments]\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":4.7,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.0,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-362\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"4.5\",\"versionEndExcluding\":\"5.10.253\",\"matchCriteriaId\":\"5817BDB6-4C64-4AB6-83FF-CC693A5E4906\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.11\",\"versionEndExcluding\":\"5.15.203\",\"matchCriteriaId\":\"20DDB3E9-AABF-4107-ADB0-5362AA067045\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.16\",\"versionEndExcluding\":\"6.1.168\",\"matchCriteriaId\":\"E2DDDCA1-6DAB-4018-B920-8F045DDD8D3B\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.2\",\"versionEndExcluding\":\"6.6.134\",\"matchCriteriaId\":\"F56F925B-BAF8-4F4B-B62F-1496AF19A307\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.7\",\"versionEndExcluding\":\"6.12.81\",\"matchCriteriaId\":\"6EF80433-B33B-43C5-8E64-0FA7B8DCE1BC\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.13\",\"versionEndExcluding\":\"6.18.21\",\"matchCriteriaId\":\"ED39847A-3B46-4729-B7CA-B2C30B9FA8FE\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.19\",\"versionEndExcluding\":\"6.19.11\",\"matchCriteriaId\":\"4CA2E747-A9EC-4518-9AA2-B4247FC748B7\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"F253B622-8837-4245-BCE5-A7BF8FC76A16\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*\",\"matchCriteriaId\":\"F666C8D8-6538-46D4-B318-87610DE64C34\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*\",\"matchCriteriaId\":\"02259FDA-961B-47BC-AE7F-93D7EC6E90C2\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*\",\"matchCriteriaId\":\"58A9FEFF-C040-420D-8F0A-BFDAAA1DF258\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/426ee10711586617da869c8bb798214965337617\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/4c5e7f0fcd592801c9cc18f29f80fbee84eb8669\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/722cfaf6b31d31123439e67b5deac6b1261a3dea\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/7ad1997b9bc8032603df8f091761114479285769\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/7ddcf4a245c1c5a91fdd9698757e3d95179ffe41\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/b8c49ad888892ad7b77062b9c102b799a3e9b4f8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.