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GHSA-W2RW-4PC9-V672

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33
VLAI
Details

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

configfs_lookup(): don't leave ->s_dentry dangling on failure

Normally ->s_dentry is cleared when dentry it's pointing to becomes negative (on eviction, realistically). However, that only happens if dentry gets to be positive in the first place; in case of inode allocation failure dentry never becomes positive, so ->d_iput() is not called at all.

We do part of what normally would've been done by configfs_d_iput() (dropping the reference to configfs_dirent) manually, but we do not clear ->s_dentry there. Sloppy as it is, it does not matter in case of configfs_create_{dir,link}() - there configfs_dirent does not survive dropping the sole reference to it.

However, for configfs_lookup() it does survive, with a dangling pointer to soon to be freed dentry sitting it its ->s_dentry.

Subsequent getdents(2) in that directory will end up dereferencing that pointer in order to pick the inode number. Use after free...

This is the minimal fix; the right approach is to set the linkage between dentry and configfs_dirent only after we know that we have an inode, but that takes more surgery and the bug had been there since 2006, so...

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-74359"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:22:37Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nconfigfs_lookup(): don\u0027t leave -\u003es_dentry dangling on failure\n\nNormally -\u003es_dentry is cleared when dentry it\u0027s pointing to becomes\nnegative (on eviction, realistically).  However, that only happens\nif dentry gets to be positive in the first place; in case of inode\nallocation failure dentry never becomes positive, so -\u003ed_iput()\nis not called at all.\n\nWe do part of what normally would\u0027ve been done by configfs_d_iput()\n(dropping the reference to configfs_dirent) manually, but we do\nnot clear -\u003es_dentry there.  Sloppy as it is, it does not matter in\ncase of configfs_create_{dir,link}() - there configfs_dirent does\nnot survive dropping the sole reference to it.\n\nHowever, for configfs_lookup() it *does* survive, with a dangling\npointer to soon to be freed dentry sitting it its -\u003es_dentry.\n\nSubsequent getdents(2) in that directory will end up dereferencing\nthat pointer in order to pick the inode number.  Use after free...\n\nThis is the minimal fix; the right approach is to set the linkage\nbetween dentry and configfs_dirent only after we know that we have\nan inode, but that takes more surgery and the bug had been there\nsince 2006, so...",
  "id": "GHSA-w2rw-4pc9-v672",
  "modified": "2026-08-17T06:33:40Z",
  "published": "2026-08-15T06:32:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74359"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/10da12d352b7b2bb330a8609fdda9a58bf0e9856"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3e83b2203aa59bd279e4f677ec793d49dc9d019e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/57088b06109f3222963c639d8d743f42c2899b13"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9c747dcee164ead300de90550ad9e4122f0d1bbb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b6e9c82522ddaa3ac0706b295ff4a71975d4f883"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c3b073a209a9baa691b744318ac929fecdd8847c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eee07d769da5ac4e4f7bd0bc17828646a318d499"
    }
  ],
  "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"
    }
  ]
}



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