{"id":"CVE-2025-40287","title":"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","summary":"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…","severity":"none","published":"2025-12-06","updated":"2026-10-15","sourceUpdated":"2026-10-15T19:10:00.173","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-40287","references":[{"url":"https://git.kernel.org/stable/c/204b1b02ee018ba52ad2ece21fe3a8643d66a1b2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6c627bcc1896ba62ec793d0c00da74f3c93ce3ad","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/82ebecdc74ff555daf70b811d854b1f32a296bea","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd"],"epss":0.00185,"epssPercentile":0.07569,"ingestedAt":"2026-10-15T19:25:46.336Z","slug":"CVE-2025-40287","body":"## Overview\n\nIn 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 — SYS_openat, SYS_ftruncate, and\nSYS_pwrite64 — 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}