{"cve":"CVE-2026-89640","nvd":{"published":"2026-09-11T20:19:49.733","modified":"2026-10-19T09:18:01.153","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: fix loff_t underflow in cifs_remap_file_range() when len == 0\n\nWith len == 0 (clone to EOF), the effective length is computed as:\n\n    len = src_inode->i_size - off;\n\nIf off > i_size, this is a negative loff_t, corrupting the ByteCount\nin the FSCTL_DUPLICATE_EXTENTS_TO_FILE request and inverting the range\nin filemap_write_and_wait_range().  The existing off >= i_size check\nfires only after the ioctl has already been sent.\n\nSnapshot i_size_read() once for both the bounds check and the length\ncalculation, eliminating the TOCTOU and 32-bit torn-read risk.  Reject\noff > src_size with -EINVAL.  Treat off == src_size as a no-op,\nconsistent with __generic_remap_file_range_prep().","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:H/A:H","score":7.1},"cwes":[],"references":["https://git.kernel.org/stable/c/6c322f5cf7476ded7a9a20f7be72462065a03c68","https://git.kernel.org/stable/c/7f62817fe049b0f3652518c1ba72631ec1e0a322","https://git.kernel.org/stable/c/b057ca17b656345d04669cb87f2aff9b31d873db","https://git.kernel.org/stable/c/b098f5e5858797827666e6cd73033f52fc39b5f6","https://git.kernel.org/stable/c/c2a0dcb5a7a1516aa6eb6d5cedca6a8e76527028"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-89640","score":0.00126,"percentile":0.02273,"date":"2026-10-25"},"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."]}