Vulnerability-Lookup

GHSA-FFF5-56XF-G7V8

Vulnerability from github – Published: 2026-05-27 15:33 – Updated: 2026-05-30 12:30

Details

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

fs: afs: revert mmap_prepare() change

Partially reverts commit 9d5403b1036c ("fs: convert most other generic_file_*mmap() users to .mmap_prepare()").

This is because the .mmap invocation establishes a refcount, but .mmap_prepare is called at a point where a merge or an allocation failure might happen after the call, which would leak the refcount increment.

Functionality is being added to permit the use of .mmap_prepare in this case, but in the interim, we need to fix this.

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-46100"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-27T14:17:31Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs: afs: revert mmap_prepare() change\n\nPartially reverts commit 9d5403b1036c (\"fs: convert most other\ngeneric_file_*mmap() users to .mmap_prepare()\").\n\nThis is because the .mmap invocation establishes a refcount, but\n.mmap_prepare is called at a point where a merge or an allocation failure\nmight happen after the call, which would leak the refcount increment.\n\nFunctionality is being added to permit the use of .mmap_prepare in this\ncase, but in the interim, we need to fix this.",
  "id": "GHSA-fff5-56xf-g7v8",
  "modified": "2026-05-30T12:30:24Z",
  "published": "2026-05-27T15:33:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46100"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/48c7a0eaeea41da17d1d84d2d7a4c40be122b246"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f51f85c044809fbd39ac8ae07ac99bc43ce32bd5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fbfc6578eaca12daa0c09df1e9ba7f2c657b49da"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-46100 (GCVE-0-2026-46100)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:59 – Updated: 2026-08-05 12:29

Title

fs: afs: revert mmap_prepare() change

Summary

In the Linux kernel, the following vulnerability has been resolved: fs: afs: revert mmap_prepare() change Partially reverts commit 9d5403b1036c ("fs: convert most other generic_file_*mmap() users to .mmap_prepare()"). This is because the .mmap invocation establishes a refcount, but .mmap_prepare is called at a point where a merge or an allocation failure might happen after the call, which would leak the refcount increment. Functionality is being added to permit the use of .mmap_prepare in this case, but in the interim, we need to fix this.

Severity

7.8 (High)


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

Assigner

Linux mitre root Scorecard

References

3 references

URL	Tags
https://git.kernel.org/stable/c/f51f85c044809fbd3…
https://git.kernel.org/stable/c/48c7a0eaeea41da17…
https://git.kernel.org/stable/c/fbfc6578eaca12daa…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 9d5403b1036cdcd4be0f9f5568612c0e60e73d79 , < f51f85c044809fbd39ac8ae07ac99bc43ce32bd5 (git) Affected: 9d5403b1036cdcd4be0f9f5568612c0e60e73d79 , < 48c7a0eaeea41da17d1d84d2d7a4c40be122b246 (git) Affected: 9d5403b1036cdcd4be0f9f5568612c0e60e73d79 , < fbfc6578eaca12daa0c09df1e9ba7f2c657b49da (git)
Linux	Linux	Affected: 6.17 Unaffected: 0 , < 6.17 (semver) Unaffected: 6.18.27 , ≤ 6.18.* (semver) Unaffected: 7.0.4 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/afs/file.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "f51f85c044809fbd39ac8ae07ac99bc43ce32bd5",
              "status": "affected",
              "version": "9d5403b1036cdcd4be0f9f5568612c0e60e73d79",
              "versionType": "git"
            },
            {
              "lessThan": "48c7a0eaeea41da17d1d84d2d7a4c40be122b246",
              "status": "affected",
              "version": "9d5403b1036cdcd4be0f9f5568612c0e60e73d79",
              "versionType": "git"
            },
            {
              "lessThan": "fbfc6578eaca12daa0c09df1e9ba7f2c657b49da",
              "status": "affected",
              "version": "9d5403b1036cdcd4be0f9f5568612c0e60e73d79",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/afs/file.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.17"
            },
            {
              "lessThan": "6.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.27",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.27",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.4",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs: afs: revert mmap_prepare() change\n\nPartially reverts commit 9d5403b1036c (\"fs: convert most other\ngeneric_file_*mmap() users to .mmap_prepare()\").\n\nThis is because the .mmap invocation establishes a refcount, but\n.mmap_prepare is called at a point where a merge or an allocation failure\nmight happen after the call, which would leak the refcount increment.\n\nFunctionality is being added to permit the use of .mmap_prepare in this\ncase, but in the interim, we need to fix this."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The refcount leak is set up by a local mmap() syscall on a file in a mounted AFS volume; although AFS is a network filesystem, the vulnerable code path is reached via a local syscall, not via remote packet processing.\nAC:L - A local user reliably forces the leaking path by mmap\u0027ing adjacent compatible regions to cause a VMA merge after .mmap_prepare; the merge and the subsequent fileserver-driven open_mmaps traversal are repeatable and within the attacker\u0027s control.\nPR:L - Exploitation requires only an unprivileged local account able to open and mmap a readable file on the AFS mount; no elevated capabilities are needed.\nUI:N - The attacker performs the mmap themselves; no action by another user is required (the AFS mount is environmental setup, not interaction).\nS:U - The corrupted vnode and the impacted callback-break code are all within the kernel\u0027s own security authority; no boundary such as VM/IOMMU is crossed.\nC:H - The leaked refcount leaves a freed afs_vnode linked on open_mmaps, and a subsequent callback-break traversal yields a use-after-free whose freed slab object can be controlled to enable arbitrary kernel memory disclosure.\nI:H - The use-after-free on the afs_vnode (afs_inode_cachep) permits heap spraying of attacker-controlled contents, providing a write primitive and potential control-flow hijack.\nA:H - The dangling list entry causes kernel oops/panic on the next callback-break traversal, and sustained triggering also leaks vnodes, so availability is fully impacted."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:29:37.582Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/f51f85c044809fbd39ac8ae07ac99bc43ce32bd5"
        },
        {
          "url": "https://git.kernel.org/stable/c/48c7a0eaeea41da17d1d84d2d7a4c40be122b246"
        },
        {
          "url": "https://git.kernel.org/stable/c/fbfc6578eaca12daa0c09df1e9ba7f2c657b49da"
        }
      ],
      "title": "fs: afs: revert mmap_prepare() change",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46100",
    "datePublished": "2026-05-27T12:59:06.853Z",
    "dateReserved": "2026-05-13T15:03:33.097Z",
    "dateUpdated": "2026-08-05T12:29:37.582Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

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.
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GHSA-FFF5-56XF-G7V8

CVE-2026-46100 (GCVE-0-2026-46100)

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