CVE-2026-90277 (GCVE-0-2026-90277)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:08 – Updated: 2026-09-17 16:08
VLAI
Title
md/md-llbitmap: prevent create failure bitmap UAF
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 5ab829f1971dc99f2aac10846c378e67fc875abc , < 930cc4f1af5a1afcd545a6ba00e38921ff8401e0 (git)
Affected: 5ab829f1971dc99f2aac10846c378e67fc875abc , < 2f0722435ce3a844dbb66b9bb0a18229dcc8739c (git)
Affected: 5ab829f1971dc99f2aac10846c378e67fc875abc , < 2116c2f0a0e547615886900e2ed8c529c016499b (git)
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Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.52 , ≤ 6.18.* (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
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          "programFiles": [
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          "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."
        }
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        "dateUpdated": "2026-09-17T16:08:09.328Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/2116c2f0a0e547615886900e2ed8c529c016499b"
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      "title": "md/md-llbitmap: prevent create failure bitmap UAF",
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    "datePublished": "2026-09-17T16:08:09.328Z",
    "dateReserved": "2026-09-11T19:38:34.797Z",
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          {
            "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."
          }
        ],
        "id": "CVE-2026-90277",
        "lastModified": "2026-09-17T17:17:24.353",
        "metrics": {},
        "published": "2026-09-17T17:17:24.353",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
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}



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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.

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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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