CVE-2026-90277 (GCVE-0-2026-90277)
Vulnerability from cvelistv5
Published
2026-09-17 16:08
Modified
2026-10-19 09:00
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: md/md-llbitmap: prevent create failure bitmap UAF llbitmap_create() publishes mddev->bitmap before reading the bitmap superblock. This is needed because llbitmap_read_sb() can initialize a new bitmap and flush it through helpers that use mddev->bitmap. If llbitmap_read_sb() fails, the old cleanup dropped bitmap_info.mutex and freed llbitmap before clearing mddev->bitmap. Readers such as /proc/mdstat rely on bitmap_info.mutex to keep the bitmap pointer stable while collecting bitmap stats, so they could observe the stale pointer after the failed create path released the mutex. Clear mddev->bitmap while still holding bitmap_info.mutex, then free the failed llbitmap after dropping the mutex. This makes mutex-protected readers see either a live bitmap or no bitmap.
References
Impacted products
Vendor Product Version
Linux Linux Version: 5ab829f1971dc99f2aac10846c378e67fc875abc
Version: 5ab829f1971dc99f2aac10846c378e67fc875abc
Version: 5ab829f1971dc99f2aac10846c378e67fc875abc
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/md-llbitmap.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "930cc4f1af5a1afcd545a6ba00e38921ff8401e0",
              "status": "affected",
              "version": "5ab829f1971dc99f2aac10846c378e67fc875abc",
              "versionType": "git"
            },
            {
              "lessThan": "2f0722435ce3a844dbb66b9bb0a18229dcc8739c",
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/md-llbitmap.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd/md-llbitmap: prevent create failure bitmap UAF\n\nllbitmap_create() publishes mddev-\u003ebitmap before reading the bitmap\nsuperblock. This is needed because llbitmap_read_sb() can initialize a\nnew bitmap and flush it through helpers that use mddev-\u003ebitmap.\n\nIf llbitmap_read_sb() fails, the old cleanup dropped bitmap_info.mutex\nand freed llbitmap before clearing mddev-\u003ebitmap. Readers such as\n/proc/mdstat rely on bitmap_info.mutex to keep the bitmap pointer stable\nwhile collecting bitmap stats, so they could observe the stale pointer\nafter the failed create path released the mutex.\n\nClear mddev-\u003ebitmap while still holding bitmap_info.mutex, then free the\nfailed llbitmap after dropping the mutex. This makes mutex-protected\nreaders see either a live bitmap or no bitmap."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:00:54.917Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/930cc4f1af5a1afcd545a6ba00e38921ff8401e0"
        },
        {
          "url": "https://git.kernel.org/stable/c/2f0722435ce3a844dbb66b9bb0a18229dcc8739c"
        },
        {
          "url": "https://git.kernel.org/stable/c/2116c2f0a0e547615886900e2ed8c529c016499b"
        }
      ],
      "title": "md/md-llbitmap: prevent create failure bitmap UAF",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90277",
    "datePublished": "2026-09-17T16:08:09.328Z",
    "dateReserved": "2026-09-11T19:38:34.797Z",
    "dateUpdated": "2026-10-19T09:00:54.917Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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