FKIE_CVE-2025-40287

Vulnerability from fkie_nvd - Published: 2025-12-06 22:15 - Updated: 2025-12-08 18:26
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: exfat: fix improper check of dentry.stream.valid_size We found an infinite loop bug in the exFAT file system that can lead to a Denial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is malformed, the following system calls — SYS_openat, SYS_ftruncate, and SYS_pwrite64 — can cause the kernel to hang. Root cause analysis shows that the size validation code in exfat_find() does not check whether dentry.stream.valid_size is negative. As a result, the system calls mentioned above can succeed and eventually trigger the DoS issue. This patch adds a check for negative dentry.stream.valid_size to prevent this vulnerability.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/204b1b02ee018ba52ad2ece21fe3a8643d66a1b2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6c627bcc1896ba62ec793d0c00da74f3c93ce3ad
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/82ebecdc74ff555daf70b811d854b1f32a296bea
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nexfat: fix improper check of dentry.stream.valid_size\n\nWe found an infinite loop bug in the exFAT file system that can lead to a\nDenial-of-Service (DoS) condition. When a dentry in an exFAT filesystem is\nmalformed, the following system calls \u2014 SYS_openat, SYS_ftruncate, and\nSYS_pwrite64 \u2014 can cause the kernel to hang.\n\nRoot cause analysis shows that the size validation code in exfat_find()\ndoes not check whether dentry.stream.valid_size is negative. As a result,\nthe system calls mentioned above can succeed and eventually trigger the DoS\nissue.\n\nThis patch adds a check for negative dentry.stream.valid_size to prevent\nthis vulnerability."
    }
  ],
  "id": "CVE-2025-40287",
  "lastModified": "2025-12-08T18:26:49.133",
  "metrics": {},
  "published": "2025-12-06T22:15:56.927",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/204b1b02ee018ba52ad2ece21fe3a8643d66a1b2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6c627bcc1896ba62ec793d0c00da74f3c93ce3ad"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/82ebecdc74ff555daf70b811d854b1f32a296bea"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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