{"cve":"CVE-2025-71237","nvd":{"published":"2026-02-18T16:22:30.517","modified":"2026-06-17T10:03:55.790","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnilfs2: Fix potential block overflow that cause system hang\n\nWhen a user executes the FITRIM command, an underflow can occur when\ncalculating nblocks if end_block is too small. Since nblocks is of\ntype sector_t, which is u64, a negative nblocks value will become a\nvery large positive integer. This ultimately leads to the block layer\nfunction __blkdev_issue_discard() taking an excessively long time to\nprocess the bio chain, and the ns_segctor_sem lock remains held for a\nlong period. This prevents other tasks from acquiring the ns_segctor_sem\nlock, resulting in the hang reported by syzbot in [1].\n\nIf the ending block is too small, typically if it is smaller than 4KiB\nrange, depending on the usage of the segment 0, it may be possible to\nattempt a discard request beyond the device size causing the hang.\n\nExiting successfully and assign the discarded size (0 in this case)\nto range->len.\n\nAlthough the start and len values in the user input range are too small,\na conservative strategy is adopted here to safely ignore them, which is\nequivalent to a no-op; it will not perform any trimming and will not\nthrow an error.\n\n[1]\ntask:segctord state:D stack:28968 pid:6093 tgid:6093  ppid:2 task_flags:0x200040 flags:0x00080000\nCall Trace:\n rwbase_write_lock+0x3dd/0x750 kernel/locking/rwbase_rt.c:272\n nilfs_transaction_lock+0x253/0x4c0 fs/nilfs2/segment.c:357\n nilfs_segctor_thread_construct fs/nilfs2/segment.c:2569 [inline]\n nilfs_segctor_thread+0x6ec/0xe00 fs/nilfs2/segment.c:2684\n\n[ryusuke: corrected part of the commit message about the consequences]","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":[],"references":["https://git.kernel.org/stable/c/2438982f635e6cc2009be68ba2efb2998727d8d4","https://git.kernel.org/stable/c/4aa45f841413cca81882602b4042c53502f34cad","https://git.kernel.org/stable/c/6457d3ee41a4c15082ac49c5aa7fb933b4a043f3","https://git.kernel.org/stable/c/b8c5ee234bd54f1447c846101fdaef2cf70c2149","https://git.kernel.org/stable/c/ba18e5f22f26aa4ef78bc3e81f639d1d4f3845e6"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:23:35.260773158+00:00"},"epss":{"cve":"CVE-2025-71237","score":0.00139,"percentile":0.03232,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}