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CVE-2026-89645 (GCVE-0-2026-89645)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:45 – Updated: 2026-09-11 19:45
VLAI
Title
btrfs: drop recovered reloc root refs on recovery failure
Summary
In the Linux kernel, the following vulnerability has been resolved: btrfs: drop recovered reloc root refs on recovery failure During relocation recovery, each fs root gets a reference to its relocation root. If loading or adding a later root fails, or if the first transaction commit fails, btrfs_recover_relocation() jumps to out_unset before merge_reloc_roots() and clean_dirty_subvols(). put_reloc_control() drops the list-owned relocation root references, but it does not clear fs_root->reloc_root or drop the references owned by those pointers. Mount cleanup only drops them when BTRFS_FS_ERROR is set, so an error such as -ENOMEM while processing a later root can leave references behind. Keep temporary references to the fs roots associated during recovery. On failure, clear their reloc_root pointers and drop the corresponding references. Once the first transaction commit succeeds, drop only the temporary fs root references and let the normal merge and cleanup paths handle the relocation roots. Fault injection on a pending-relocation image confirmed the cleanup gap. With an injected first-commit failure, 25 fs roots had reloc_root set with fs_error=0. With this fix, the same failure path drops that count to 0 before mount fails.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f44deb7442edf42abee6be25fca7e3e86061b4c9 , < 2256d6dc5b88841a8a8b4fd9a9f04730705fb6fd (git)
Affected: f44deb7442edf42abee6be25fca7e3e86061b4c9 , < 8a64baeb5bbb706b83d2235c1e39f5b77183817f (git)
Affected: f44deb7442edf42abee6be25fca7e3e86061b4c9 , < 4d43107e807bcd92621106b07f5011411c6341a8 (git)
Affected: f44deb7442edf42abee6be25fca7e3e86061b4c9 , < 6d8ba4572922e336f0b59a80751b018e1e135164 (git)
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Linux Linux Affected: 5.7
Unaffected: 0 , < 5.7 (semver)
Unaffected: 6.12.109 , ≤ 6.12.* (semver)
Unaffected: 6.18.50 , ≤ 6.18.* (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/relocation.c"
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      "descriptions": [
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: drop recovered reloc root refs on recovery failure\n\nDuring relocation recovery, each fs root gets a reference to its relocation\nroot. If loading or adding a later root fails, or if the first transaction\ncommit fails, btrfs_recover_relocation() jumps to out_unset before\nmerge_reloc_roots() and clean_dirty_subvols().\n\nput_reloc_control() drops the list-owned relocation root references, but it\ndoes not clear fs_root-\u003ereloc_root or drop the references owned by those\npointers. Mount cleanup only drops them when BTRFS_FS_ERROR is set, so an\nerror such as -ENOMEM while processing a later root can leave references\nbehind.\n\nKeep temporary references to the fs roots associated during recovery. On\nfailure, clear their reloc_root pointers and drop the corresponding\nreferences. Once the first transaction commit succeeds, drop only the\ntemporary fs root references and let the normal merge and cleanup paths\nhandle the relocation roots.\n\nFault injection on a pending-relocation image confirmed the cleanup gap.\nWith an injected first-commit failure, 25 fs roots had reloc_root set with\nfs_error=0. With this fix, the same failure path drops that count to 0\nbefore mount fails."
        }
      ],
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        "shortName": "Linux"
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    "cveId": "CVE-2026-89645",
    "datePublished": "2026-09-11T19:45:37.016Z",
    "dateReserved": "2026-09-11T19:38:34.741Z",
    "dateUpdated": "2026-09-11T19:45:37.016Z",
    "state": "PUBLISHED"
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      "initial_release_date": "2026-09-13T01:09:25.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "btrfs: drop recovered reloc root refs on recovery failure",
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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.

Sightings

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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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.