GHSA-XRHF-CCCW-CPM8

Vulnerability from github – Published: 2024-10-21 18:30 – Updated: 2025-11-04 00:31
VLAI?
Details

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

ext4: fix timer use-after-free on failed mount

Syzbot has found an ODEBUG bug in ext4_fill_super

The del_timer_sync function cancels the s_err_report timer, which reminds about filesystem errors daily. We should guarantee the timer is no longer active before kfree(sbi).

When filesystem mounting fails, the flow goes to failed_mount3, where an error occurs when ext4_stop_mmpd is called, causing a read I/O failure. This triggers the ext4_handle_error function that ultimately re-arms the timer, leaving the s_err_report timer active before kfree(sbi) is called.

Fix the issue by canceling the s_err_report timer after calling ext4_stop_mmpd.

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-2024-49960"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-10-21T18:15:17Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\next4: fix timer use-after-free on failed mount\n\nSyzbot has found an ODEBUG bug in ext4_fill_super\n\nThe del_timer_sync function cancels the s_err_report timer,\nwhich reminds about filesystem errors daily. We should\nguarantee the timer is no longer active before kfree(sbi).\n\nWhen filesystem mounting fails, the flow goes to failed_mount3,\nwhere an error occurs when ext4_stop_mmpd is called, causing\na read I/O failure. This triggers the ext4_handle_error function\nthat ultimately re-arms the timer,\nleaving the s_err_report timer active before kfree(sbi) is called.\n\nFix the issue by canceling the s_err_report timer after calling ext4_stop_mmpd.",
  "id": "GHSA-xrhf-cccw-cpm8",
  "modified": "2025-11-04T00:31:43Z",
  "published": "2024-10-21T18:30:58Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-49960"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0ce160c5bdb67081a62293028dc85758a8efb22a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/22e9b83f0f33bc5a7a3181769d1dccbf021f5b04"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7aac0c17a8cdf4a3236991c1e60435c6a984076c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9203817ba46ebba7c865c8de2aba399537b6e891"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b85569585d0154d4db1e4f9e3e6a4731d407feb0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cf3196e5e2f36cd80dab91ffae402e13935724bc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fa78fb51d396f4f2f80f8e96a3b1516f394258be"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.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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