Vulnerability-Lookup

GHSA-7JRV-8XMF-X8J2

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-25 06:31

Details

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

fscrypt: use the mount idmap for the owner check in fscrypt_ioctl_set_policy()

fscrypt_ioctl_set_policy() calls inode_owner_or_capable() with &nop_mnt_idmap before allowing an encryption policy to be set, instead of the idmap of the mount the ioctl was issued on.

fscrypt is used by filesystems that support idmapped mounts (e.g. ext4, f2fs), so on such a mount this compares the caller's fsuid against the unmapped on-disk owner rather than the mapped owner: the actual owner can be wrongly denied with -EACCES and an unrelated caller wrongly allowed. Use file_mnt_idmap(filp) instead.

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-2026-74595"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:31Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfscrypt: use the mount idmap for the owner check in fscrypt_ioctl_set_policy()\n\nfscrypt_ioctl_set_policy() calls inode_owner_or_capable() with\n\u0026nop_mnt_idmap before allowing an encryption policy to be set, instead\nof the idmap of the mount the ioctl was issued on.\n\nfscrypt is used by filesystems that support idmapped mounts (e.g. ext4,\nf2fs), so on such a mount this compares the caller\u0027s fsuid against the\nunmapped on-disk owner rather than the mapped owner: the actual owner\ncan be wrongly denied with -EACCES and an unrelated caller wrongly\nallowed.  Use file_mnt_idmap(filp) instead.",
  "id": "GHSA-7jrv-8xmf-x8j2",
  "modified": "2026-08-25T06:31:21Z",
  "published": "2026-08-22T18:30:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74595"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0baeb730044981f5ec5fb7d62a3763835ea606f6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/174633a468817a49bd474bcfc9067c84e54efe68"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/33b7e810ce09955aa02f3b632455cf5e7ac990a9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/653e888a24c87b8bbeab44d7e558a1c1a3641088"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6a67c460b12315033268dce597546984fe5739e7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/98516ba8b817f34e86bdd7a5b7a383cff75c3ddf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cf6c993c0feca7984797e634deba3c80342e199a"
    }
  ],
  "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-2026-74595 (GCVE-0-2026-74595)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:31 – Updated: 2026-08-25 05:40

Title

fscrypt: use the mount idmap for the owner check in fscrypt_ioctl_set_policy()

Summary

In the Linux kernel, the following vulnerability has been resolved: fscrypt: use the mount idmap for the owner check in fscrypt_ioctl_set_policy() fscrypt_ioctl_set_policy() calls inode_owner_or_capable() with &nop_mnt_idmap before allowing an encryption policy to be set, instead of the idmap of the mount the ioctl was issued on. fscrypt is used by filesystems that support idmapped mounts (e.g. ext4, f2fs), so on such a mount this compares the caller's fsuid against the unmapped on-disk owner rather than the mapped owner: the actual owner can be wrongly denied with -EACCES and an unrelated caller wrongly allowed. Use file_mnt_idmap(filp) instead.

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

References

7 references

URL	Tags
https://git.kernel.org/stable/c/174633a468817a49b…
https://git.kernel.org/stable/c/0baeb730044981f5e…
https://git.kernel.org/stable/c/33b7e810ce09955aa…
https://git.kernel.org/stable/c/6a67c460b12315033…
https://git.kernel.org/stable/c/653e888a24c87b8bb…
https://git.kernel.org/stable/c/98516ba8b817f34e8…
https://git.kernel.org/stable/c/cf6c993c0feca7984…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 14f3db5542e62bcf6fe088a09760ac52d55306c5 , < 174633a468817a49bd474bcfc9067c84e54efe68 (git) Affected: 14f3db5542e62bcf6fe088a09760ac52d55306c5 , < 0baeb730044981f5ec5fb7d62a3763835ea606f6 (git) Affected: 14f3db5542e62bcf6fe088a09760ac52d55306c5 , < 33b7e810ce09955aa02f3b632455cf5e7ac990a9 (git) Affected: 14f3db5542e62bcf6fe088a09760ac52d55306c5 , < 6a67c460b12315033268dce597546984fe5739e7 (git) Affected: 14f3db5542e62bcf6fe088a09760ac52d55306c5 , < 653e888a24c87b8bbeab44d7e558a1c1a3641088 (git) Affected: 14f3db5542e62bcf6fe088a09760ac52d55306c5 , < 98516ba8b817f34e86bdd7a5b7a383cff75c3ddf (git) Affected: 14f3db5542e62bcf6fe088a09760ac52d55306c5 , < cf6c993c0feca7984797e634deba3c80342e199a (git)
Linux	Linux	Affected: 5.12 Unaffected: 0 , < 5.12 (semver) Unaffected: 5.15.217 , ≤ 5.15.* (semver) Unaffected: 6.1.184 , ≤ 6.1.* (semver) Unaffected: 6.6.152 , ≤ 6.6.* (semver) Unaffected: 6.12.104 , ≤ 6.12.* (semver) Unaffected: 6.18.45 , ≤ 6.18.* (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/crypto/policy.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "174633a468817a49bd474bcfc9067c84e54efe68",
              "status": "affected",
              "version": "14f3db5542e62bcf6fe088a09760ac52d55306c5",
              "versionType": "git"
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            {
              "lessThan": "0baeb730044981f5ec5fb7d62a3763835ea606f6",
              "status": "affected",
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              "lessThan": "33b7e810ce09955aa02f3b632455cf5e7ac990a9",
              "status": "affected",
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            },
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              "versionType": "git"
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            {
              "lessThan": "98516ba8b817f34e86bdd7a5b7a383cff75c3ddf",
              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "cf6c993c0feca7984797e634deba3c80342e199a",
              "status": "affected",
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              "versionType": "git"
            }
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          "versions": [
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              "version": "5.12"
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "5.15.217",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.184",
              "versionType": "semver"
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              "version": "6.6.152",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
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        {
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfscrypt: use the mount idmap for the owner check in fscrypt_ioctl_set_policy()\n\nfscrypt_ioctl_set_policy() calls inode_owner_or_capable() with\n\u0026nop_mnt_idmap before allowing an encryption policy to be set, instead\nof the idmap of the mount the ioctl was issued on.\n\nfscrypt is used by filesystems that support idmapped mounts (e.g. ext4,\nf2fs), so on such a mount this compares the caller\u0027s fsuid against the\nunmapped on-disk owner rather than the mapped owner: the actual owner\ncan be wrongly denied with -EACCES and an unrelated caller wrongly\nallowed.  Use file_mnt_idmap(filp) instead."
        }
      ],
      "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 - Exploitation requires a local process to open a directory on an idmapped ext4/f2fs filesystem and issue FS_IOC_SET_ENCRYPTION_POLICY via ioctl(); there is no network, adjacent-radio, or physical-device attack path to the vulnerable fscrypt_ioctl_set_policy() check.\nAC:L - On idmapped mounts the UID mismatch is structural, not random: any local user whose fsuid equals the inode\u0027s unmapped on-disk owner can open an empty victim directory, add their own fscrypt key, and trigger the ioctl without races or attacker-uncontrollable memory layout.\nPR:L - Only basic local user privileges are needed; the attacker must be able to open the target directory and call FS_IOC_ADD_ENCRYPTION_KEY plus FS_IOC_SET_ENCRYPTION_POLICY, with no real-root or init-namespace capability required beyond normal DAC permissions on the path.\nUI:N - Exploitation requires no action by the victim; the attacker alone issues the ioctl on an empty directory they can open, and the authorization bypass occurs entirely within the attacker\u0027s own syscall sequence.\nS:U - This is an incorrect inode_owner_or_capable() authorization check in the kernel fscrypt ioctl path on idmapped mounts; impact stays within the same kernel security authority and does not constitute VM escape, hypervisor bypass, or IOMMU boundary crossing.\nC:H - A wrongly authorized attacker can bind a victim\u0027s empty directory to an attacker-controlled fscrypt master key, then decrypt any sensitive files the victim later creates there, giving broad read access to victim data rather than a small bounded leak.\nI:H - The ioctl persistently modifies filesystem encryption policy and on-disk fscrypt context for a directory the attacker does not own, granting unauthorized control over a critical security property of victim data at rest.\nA:H - The bug both wrongly denies legitimate directory owners with -EACCES and lets attackers encrypt a victim\u0027s empty directory with an attacker-held key, preventing the real owner from using or recovering that directory and its future contents."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T05:40:22.483Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/174633a468817a49bd474bcfc9067c84e54efe68"
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          "url": "https://git.kernel.org/stable/c/0baeb730044981f5ec5fb7d62a3763835ea606f6"
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        },
        {
          "url": "https://git.kernel.org/stable/c/98516ba8b817f34e86bdd7a5b7a383cff75c3ddf"
        },
        {
          "url": "https://git.kernel.org/stable/c/cf6c993c0feca7984797e634deba3c80342e199a"
        }
      ],
      "title": "fscrypt: use the mount idmap for the owner check in fscrypt_ioctl_set_policy()",
      "x_generator": {
        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74595",
    "datePublished": "2026-08-22T15:31:45.649Z",
    "dateReserved": "2026-08-15T05:44:03.919Z",
    "dateUpdated": "2026-08-25T05:40:22.483Z",
    "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.

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.

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GHSA-7JRV-8XMF-X8J2

CVE-2026-74595 (GCVE-0-2026-74595)

Tags

Sightings

Nomenclature