CVE-2026-80899 (GCVE-0-2026-80899)

Vulnerability from cvelistv5 – Published: 2026-09-04 17:11 – Updated: 2026-09-07 14:21
VLAI
Title
erofs: remove fscache backend entirely
Summary
In the Linux kernel, the following vulnerability has been resolved: erofs: remove fscache backend entirely EROFS over fscache was introduced to provide image lazy pulling functionality. After the feature landed, the fscache subsystem made netfs a new hard dependency, which is unexpected for a local filesystem and has an kernel-defined caching hierarchy which could be inflexible compared to the fanotify pre-content hooks. Therefore, this feature has been deprecated for almost two years. As EROFS file-backed mounts and fanotify pre-content hooks both upstream for a while and already providing equivalent functionality (erofs-utils has supported fanotify pre-content hooks), let's remove the fscache backend now. The main application of this feature is Nydus [1], and they plan to move to use fanotify pre-content hooks in the near future too. I hope this patch can be merged into Linux 7.2, which is also motivated by newly found implementation issues [2][3] that are not worth investigating given the deprecation and limited development resources. The associated fscache/cachefiles cleanup patch will follow separately through the vfs tree (netfs) later: it seems fine since the codebase is isolated by CONFIG_CACHEFILES_ONDEMAND. [1] https://github.com/dragonflyoss/nydus/blob/v2.1.0/docs/nydus-fscache.md [2] https://github.com/dragonflyoss/nydus/pull/1824 [3] https://lore.kernel.org/r/20260619135800.1594811-1-michael.bommarito@gmail.com
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: a1bafc3109d713ed83f73d61ba5cb1e6fd80fdbc , < f6145794f17a27d25f8a84edb80731fb0e07c196 (git)
Affected: a1bafc3109d713ed83f73d61ba5cb1e6fd80fdbc , < c37460cd9b2fcb61ec66b7eb4fde737e65ec2a56 (git)
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Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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            "Documentation/filesystems/erofs.rst",
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            "fs/erofs/data.c",
            "fs/erofs/fscache.c",
            "fs/erofs/inode.c",
            "fs/erofs/internal.h",
            "fs/erofs/ishare.c",
            "fs/erofs/super.c",
            "fs/erofs/zdata.c"
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        "dateUpdated": "2026-09-07T14:21:26.371Z",
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        "shortName": "Linux"
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    "cveId": "CVE-2026-80899",
    "datePublished": "2026-09-04T17:11:14.158Z",
    "dateReserved": "2026-08-26T14:34:25.800Z",
    "dateUpdated": "2026-09-07T14:21:26.371Z",
    "state": "PUBLISHED"
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      "percentile": "0.08594"
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                  "fs/erofs/fscache.c",
                  "fs/erofs/inode.c",
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                  "fs/erofs/ishare.c",
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        "descriptions": [
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nerofs: remove fscache backend entirely\n\nEROFS over fscache was introduced to provide image lazy pulling\nfunctionality. After the feature landed, the fscache subsystem made\nnetfs a new hard dependency, which is unexpected for a local filesystem\nand has an kernel-defined caching hierarchy which could be inflexible\ncompared to the fanotify pre-content hooks. Therefore, this feature has\nbeen deprecated for almost two years.\n\nAs EROFS file-backed mounts and fanotify pre-content hooks both upstream\nfor a while and already providing equivalent functionality (erofs-utils\nhas supported fanotify pre-content hooks), let\u0027s remove the fscache\nbackend now.\n\nThe main application of this feature is Nydus [1], and they plan to move\nto use fanotify pre-content hooks in the near future too.\n\nI hope this patch can be merged into Linux 7.2, which is also motivated\nby newly found implementation issues [2][3] that are not worth\ninvestigating given the deprecation and limited development resources.\nThe associated fscache/cachefiles cleanup patch will follow separately\nthrough the vfs tree (netfs) later: it seems fine since the codebase is\nisolated by CONFIG_CACHEFILES_ONDEMAND.\n\n[1] https://github.com/dragonflyoss/nydus/blob/v2.1.0/docs/nydus-fscache.md\n[2] https://github.com/dragonflyoss/nydus/pull/1824\n[3] https://lore.kernel.org/r/20260619135800.1594811-1-michael.bommarito@gmail.com"
          }
        ],
        "id": "CVE-2026-80899",
        "lastModified": "2026-09-07T15:17:33.410",
        "metrics": {},
        "published": "2026-09-04T18:17:58.170",
        "references": [
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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