github - ghsa-4rvm-hh4p-2jfj

GHSA-4RVM-HH4P-2JFJ

Vulnerability from github – Published: 2025-09-05 18:31 – Updated: 2025-12-03 21:30

Details

In the Linux kernel, the following vulnerability has been resolved:

loop: Avoid updating block size under exclusive owner

Syzbot came up with a reproducer where a loop device block size is changed underneath a mounted filesystem. This causes a mismatch between the block device block size and the block size stored in the superblock causing confusion in various places such as fs/buffer.c. The particular issue triggered by syzbot was a warning in __getblk_slow() due to requested buffer size not matching block device block size.

Fix the problem by getting exclusive hold of the loop device to change its block size. This fails if somebody (such as filesystem) has already an exclusive ownership of the block device and thus prevents modifying the loop device under some exclusive owner which doesn't expect it.

Severity ?

5.5 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2025-38709"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-09-04T16:15:39Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nloop: Avoid updating block size under exclusive owner\n\nSyzbot came up with a reproducer where a loop device block size is\nchanged underneath a mounted filesystem. This causes a mismatch between\nthe block device block size and the block size stored in the superblock\ncausing confusion in various places such as fs/buffer.c. The particular\nissue triggered by syzbot was a warning in __getblk_slow() due to\nrequested buffer size not matching block device block size.\n\nFix the problem by getting exclusive hold of the loop device to change\nits block size. This fails if somebody (such as filesystem) has already\nan exclusive ownership of the block device and thus prevents modifying\nthe loop device under some exclusive owner which doesn\u0027t expect it.",
  "id": "GHSA-4rvm-hh4p-2jfj",
  "modified": "2025-12-03T21:30:58Z",
  "published": "2025-09-05T18:31:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-38709"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/139a000d20f2f38ce34296feddd641d730fe1c08"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/457d2c5e112fd08dc1039b1ae39a83ec1782360d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5d67b30aefeb7a949040bbb1b4e3b84c5d29a624"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7e49538288e523427beedd26993d446afef1a6fb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b928438cc87c0bf7ae078e4b7b6e14261e84c5c5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ce8da5d13d8c2a7b30b2fb376a22e8eb1a70b8bb"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2025-38709 (GCVE-0-2025-38709)

Vulnerability from cvelistv5 – Published: 2025-09-04 15:32 – Updated: 2025-10-02 13:25

Summary

In the Linux kernel, the following vulnerability has been resolved: loop: Avoid updating block size under exclusive owner Syzbot came up with a reproducer where a loop device block size is changed underneath a mounted filesystem. This causes a mismatch between the block device block size and the block size stored in the superblock causing confusion in various places such as fs/buffer.c. The particular issue triggered by syzbot was a warning in __getblk_slow() due to requested buffer size not matching block device block size. Fix the problem by getting exclusive hold of the loop device to change its block size. This fails if somebody (such as filesystem) has already an exclusive ownership of the block device and thus prevents modifying the loop device under some exclusive owner which doesn't expect it.

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/457d2c5e112fd08dc…
	https://git.kernel.org/stable/c/139a000d20f2f38ce…
	https://git.kernel.org/stable/c/b928438cc87c0bf7a…
	https://git.kernel.org/stable/c/5d67b30aefeb7a949…
	https://git.kernel.org/stable/c/7e49538288e523427…

Impacted products

Vendor

Product

Version

Linux

Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 457d2c5e112fd08dc1039b1ae39a83ec1782360d (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 139a000d20f2f38ce34296feddd641d730fe1c08 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < b928438cc87c0bf7ae078e4b7b6e14261e84c5c5 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 5d67b30aefeb7a949040bbb1b4e3b84c5d29a624 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 7e49538288e523427beedd26993d446afef1a6fb (git)

Linux

Unaffected: 6.6.109 , ≤ 6.6.* (semver)
Unaffected: 6.12.43 , ≤ 6.12.* (semver)
Unaffected: 6.15.11 , ≤ 6.15.* (semver)
Unaffected: 6.16.2 , ≤ 6.16.* (semver)
Unaffected: 6.17 , ≤ * (original_commit_for_fix)

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{
  "containers": {
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        {
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          "programFiles": [
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          "vendor": "Linux",
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              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
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              "versionType": "git"
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          "vendor": "Linux",
          "versions": [
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              "status": "unaffected",
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              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
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            },
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              "status": "unaffected",
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            },
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              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-10-02T13:25:58.232Z",
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    "datePublished": "2025-09-04T15:32:59.818Z",
    "dateReserved": "2025-04-16T04:51:24.033Z",
    "dateUpdated": "2025-10-02T13:25:58.232Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.1"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

GHSA-4RVM-HH4P-2JFJ

CVE-2025-38709 (GCVE-0-2025-38709)

Tags

Sightings

Nomenclature