CVE-2026-93216 (GCVE-0-2026-93216)
Vulnerability from cvelistv5
Published
2026-09-24 15:10
Modified
2026-10-21 12:52
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg() print_page_owner_memcg() reads page->memcg_data via READ_ONCE() at the start to guard against tail pages and NULL data. However, it later re-reads page->memcg_data locklessly in two places: 1: page_memcg_check(page) 2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS) If the page is concurrently freed and reallocated as a THP tail page or slab page between these calls, the VM_BUG_ON assertions can trigger on CONFIG_DEBUG_VM=y builds, crashing the kernel. Fix both TOCTOU issues by using the memcg_data snapshot throughout.
References
Impacted products
Vendor Product Version
Linux Linux Version: fcf8935832b86d3437f00e732c6d0d4d2819d6a9
Version: fcf8935832b86d3437f00e732c6d0d4d2819d6a9
Version: fcf8935832b86d3437f00e732c6d0d4d2819d6a9
Version: fcf8935832b86d3437f00e732c6d0d4d2819d6a9
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "mm/page_owner.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.18"
            },
            {
              "lessThan": "5.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.114",
              "versionType": "semver"
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              "version": "7.2.4",
              "versionType": "semver"
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              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.160",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.114",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
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                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg()\n\nprint_page_owner_memcg() reads page-\u003ememcg_data via READ_ONCE() at the\nstart to guard against tail pages and NULL data.  However, it later\nre-reads page-\u003ememcg_data locklessly in two places:\n\n1: page_memcg_check(page)\n\n2: PageMemcgKmem(page) (via folio_memcg_kmem(), which includes\n   VM_BUG_ON assertions for tail pages and MEMCG_DATA_OBJEXTS)\n\nIf the page is concurrently freed and reallocated as a THP tail page or\nslab page between these calls, the VM_BUG_ON assertions can trigger on\nCONFIG_DEBUG_VM=y builds, crashing the kernel.\n\nFix both TOCTOU issues by using the memcg_data snapshot throughout."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:52:21.777Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e7c1923c5f30a6953f0540e3171d882ec17b05d3"
        },
        {
          "url": "https://git.kernel.org/stable/c/a4c940ab3f794f221a338c9431ad1ce0d73a2bea"
        },
        {
          "url": "https://git.kernel.org/stable/c/46761406e14381dc35f498c247a87565b87ea2ef"
        },
        {
          "url": "https://git.kernel.org/stable/c/90f095b816e25c6a9e4446d299bac5007fdcb3df"
        }
      ],
      "title": "mm/page_owner: use memcg_data snapshot to avoid TOCTOU in print_page_owner_memcg()",
      "x_generator": {
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      }
    }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93216",
    "datePublished": "2026-09-24T15:10:38.702Z",
    "dateReserved": "2026-09-17T16:02:15.093Z",
    "dateUpdated": "2026-10-21T12:52:21.777Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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