GHSA-VJWM-W9RC-F4CC

Vulnerability from github – Published: 2025-03-27 15:31 – Updated: 2025-12-07 00:30
VLAI?
Details

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

ovl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up

The issue was caused by dput(upper) being called before ovl_dentry_update_reval(), while upper->d_flags was still accessed in ovl_dentry_remote().

Move dput(upper) after its last use to prevent use-after-free.

BUG: KASAN: slab-use-after-free in ovl_dentry_remote fs/overlayfs/util.c:162 [inline] BUG: KASAN: slab-use-after-free in ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167

Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 ovl_dentry_remote fs/overlayfs/util.c:162 [inline] ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167 ovl_link_up fs/overlayfs/copy_up.c:610 [inline] ovl_copy_up_one+0x2105/0x3490 fs/overlayfs/copy_up.c:1170 ovl_copy_up_flags+0x18d/0x200 fs/overlayfs/copy_up.c:1223 ovl_rename+0x39e/0x18c0 fs/overlayfs/dir.c:1136 vfs_rename+0xf84/0x20a0 fs/namei.c:4893 ...

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-2025-21887"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-03-27T15:15:56Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\novl: fix UAF in ovl_dentry_update_reval by moving dput() in ovl_link_up\n\nThe issue was caused by dput(upper) being called before\novl_dentry_update_reval(), while upper-\u003ed_flags was still\naccessed in ovl_dentry_remote().\n\nMove dput(upper) after its last use to prevent use-after-free.\n\nBUG: KASAN: slab-use-after-free in ovl_dentry_remote fs/overlayfs/util.c:162 [inline]\nBUG: KASAN: slab-use-after-free in ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167\n\nCall Trace:\n \u003cTASK\u003e\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0xc3/0x620 mm/kasan/report.c:488\n kasan_report+0xd9/0x110 mm/kasan/report.c:601\n ovl_dentry_remote fs/overlayfs/util.c:162 [inline]\n ovl_dentry_update_reval+0xd2/0xf0 fs/overlayfs/util.c:167\n ovl_link_up fs/overlayfs/copy_up.c:610 [inline]\n ovl_copy_up_one+0x2105/0x3490 fs/overlayfs/copy_up.c:1170\n ovl_copy_up_flags+0x18d/0x200 fs/overlayfs/copy_up.c:1223\n ovl_rename+0x39e/0x18c0 fs/overlayfs/dir.c:1136\n vfs_rename+0xf84/0x20a0 fs/namei.c:4893\n...\n \u003c/TASK\u003e",
  "id": "GHSA-vjwm-w9rc-f4cc",
  "modified": "2025-12-07T00:30:54Z",
  "published": "2025-03-27T15:31:12Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21887"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3594aad97e7be2557ca9fa9c931b206b604028c8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4b49d939b5a79117f939b77cc67efae2694d9799"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/60b4b5c1277fc491da9e1e7abab307bfa39c2db7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/64455c8051c3aedc71abb7ec8d47c80301f99f00"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a7c41830ffcd17b2177a95a9b99b270302090c35"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c84e125fff2615b4d9c259e762596134eddd2f27"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f77618291836168eca99e89cd175256f928f5e64"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"
    }
  ],
  "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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