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GHSA-GH58-FMWQ-66R3

Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31

Details

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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80899"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-04T18:17:58Z",
    "severity": null
  },
  "details": "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": "GHSA-gh58-fmwq-66r3",
  "modified": "2026-09-04T18:31:34Z",
  "published": "2026-09-04T18:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80899"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c37460cd9b2fcb61ec66b7eb4fde737e65ec2a56"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f6145794f17a27d25f8a84edb80731fb0e07c196"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

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

Vulnerability from cvelistv5 – Published: 2026-09-04 17:11 – Updated: 2026-09-04 17:11

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

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/f6145794f17a27d25…
https://git.kernel.org/stable/c/c37460cd9b2fcb61e…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < f6145794f17a27d25f8a84edb80731fb0e07c196 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < c37460cd9b2fcb61ec66b7eb4fde737e65ec2a56 (git) Affected: 0 , < 7.1.8 (semver)
Linux	Linux	Unaffected: 7.1.8 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "Documentation/filesystems/erofs.rst",
            "fs/erofs/Kconfig",
            "fs/erofs/Makefile",
            "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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          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
            },
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              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
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        },
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          "defaultStatus": "affected",
          "product": "Linux",
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            "fs/erofs/inode.c",
            "fs/erofs/internal.h",
            "fs/erofs/ishare.c",
            "fs/erofs/super.c",
            "fs/erofs/zdata.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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              "versionType": "semver"
            },
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      ],
      "cpeApplicability": [
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              "cpeMatch": [
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    "datePublished": "2026-09-04T17:11:14.158Z",
    "dateReserved": "2026-08-26T14:34:25.800Z",
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}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

GHSA-GH58-FMWQ-66R3

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

Tags

Sightings

Nomenclature