CVE-2026-31589 (GCVE-0-2026-31589)
Vulnerability from cvelistv5
Published
2026-04-24 14:42
Modified
2026-08-05 12:23
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: mm: call ->free_folio() directly in folio_unmap_invalidate() We can only call filemap_free_folio() if we have a reference to (or hold a lock on) the mapping. Otherwise, we've already removed the folio from the mapping so it no longer pins the mapping and the mapping can be removed, causing a use-after-free when accessing mapping->a_ops. Follow the same pattern as __remove_mapping() and load the free_folio function pointer before dropping the lock on the mapping. That lets us make filemap_free_folio() static as this was the only caller outside filemap.c.
References
Impacted products
Vendor Product Version
Linux Linux Version: fb7d3bc4149395c1ae99029c852eab6c28fc3c88
Version: fb7d3bc4149395c1ae99029c852eab6c28fc3c88
Version: fb7d3bc4149395c1ae99029c852eab6c28fc3c88
Version: fb7d3bc4149395c1ae99029c852eab6c28fc3c88
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/filemap.c",
            "mm/internal.h",
            "mm/truncate.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "efc52947247a21bbf79059539bbbd40f4ea76f00",
              "status": "affected",
              "version": "fb7d3bc4149395c1ae99029c852eab6c28fc3c88",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "fb7d3bc4149395c1ae99029c852eab6c28fc3c88",
              "versionType": "git"
            },
            {
              "lessThan": "c330e65ea59c4805d6ab6757c4ddfe8c63acef31",
              "status": "affected",
              "version": "fb7d3bc4149395c1ae99029c852eab6c28fc3c88",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "fb7d3bc4149395c1ae99029c852eab6c28fc3c88",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "mm/filemap.c",
            "mm/internal.h",
            "mm/truncate.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.27",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.1",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.27",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.14",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.1",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: call -\u003efree_folio() directly in folio_unmap_invalidate()\n\nWe can only call filemap_free_folio() if we have a reference to (or hold a\nlock on) the mapping.  Otherwise, we\u0027ve already removed the folio from the\nmapping so it no longer pins the mapping and the mapping can be removed,\ncausing a use-after-free when accessing mapping-\u003ea_ops.\n\nFollow the same pattern as __remove_mapping() and load the free_folio\nfunction pointer before dropping the lock on the mapping.  That lets us\nmake filemap_free_folio() static as this was the only caller outside\nfilemap.c."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The vulnerable path can be reached by remote NFS clients when nfsd is configured for NFSD_IO_DONTCACHE on a filesystem advertising FOP_DONTCACHE, causing remote READ/WRITE handling to set IOCB_DONTCACHE and enter the dropbehind invalidation path. This is a network-facing kernel service.\nAC:L - Once the affected DONTCACHE path is available, an attacker can repeatedly drive writeback/dropbehind and inode lifetime pressure with ordinary I/O operations. The race is attacker-influenced rather than dependent on an uncontrollable system state.\nPR:N - A remote NFS client can reach nfsd request processing without local shell access or kernel capabilities on the target; permissive or anonymous exports make the relevant file operations reachable without prior target privileges. When uncertain between N and L, N is the higher-severity defensible choice.\nUI:N - No victim user action is needed after the service and export are available. The attacker triggers the path by sending I/O requests.\nS:U - The vulnerability corrupts/uses freed memory inside the same kernel security authority that processes the request. It is not a VM escape, IOMMU bypass, or cross-authority boundary violation.\nC:H - The bug is a use-after-free of the address_space/inode-backed mapping when dereferencing mapping-\u003ea_ops after the folio no longer pins the mapping. Kernel UAFs are defensibly scored as high confidentiality impact because they can be shaped into kernel memory disclosure primitives.\nI:H - The stale mapping dereference includes an indirect free_folio function pointer lookup and potential call, making control-flow or memory corruption exploitation defensible. Kernel UAFs are scored high for integrity under the provided guidance.\nA:H - At minimum, dereferencing mapping-\u003ea_ops after the mapping has been freed can crash or oops the kernel. The attacker can trigger the vulnerable path repeatedly, so availability impact is high."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:23:40.286Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/efc52947247a21bbf79059539bbbd40f4ea76f00"
        },
        {
          "url": "https://git.kernel.org/stable/c/b667df39d98a7a24be7c2a40ff0863dac1ad2cd7"
        },
        {
          "url": "https://git.kernel.org/stable/c/c330e65ea59c4805d6ab6757c4ddfe8c63acef31"
        },
        {
          "url": "https://git.kernel.org/stable/c/615d9bb2ccad42f9e21d837431e401db2e471195"
        }
      ],
      "title": "mm: call -\u003efree_folio() directly in folio_unmap_invalidate()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31589",
    "datePublished": "2026-04-24T14:42:16.955Z",
    "dateReserved": "2026-03-09T15:48:24.120Z",
    "dateUpdated": "2026-08-05T12:23:40.286Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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