{"cve":"CVE-2026-64159","nvd":{"published":"2026-07-19T16:17:57.913","modified":"2026-10-21T13:19:21.530","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix zeropoint update where i_size > remote_i_size\n\nFix the update of the zero point[*] by netfs_release_folio() when there is\nuncommitted data in the pagecache beyond the folio being released but the\non-server EOF is in this folio (ie. i_size > remote_i_size).  The update\nneeds to limit zero_point to remote_i_size, not i_size as i_size is a local\nphenomenon reflecting updates made locally to the pagecache, not stuff\nwritten to the server.  remote_i_size tracks the server's i_size.\n\n[*] The zero point is the file position from which we can assume that the\n    server will just return zeros, so we can avoid generating reads.\n\nNote that netfs_invalidate_folio() probably doesn't need fixing as\nzero_point should be updated by setattr after truncation or fallocate.\n\nFound with:\n\n    fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \\\n        /xfstest.test/junk --replay-ops=junk.fsxops\n\nusing the following as junk.fsxops:\n\n    truncate 0x0 0x1bbae 0x82864\n    write 0x3ef2e 0xf9c8 0x1bbae\n    write 0x67e05 0xcb5a 0x4e8f6\n    mapread 0x57781 0x85b6 0x7495f\n    copy_range 0x5d3d 0x10329 0x54fac 0x7495f\n    write 0x64710 0x1c2b 0x7495f\n    mapread 0x64000 0x1000 0x7495f\n\non cifs with the default cache option.\n\nIt shows read-gaps on folio 0x64 failing with a short read (ie. it hits\nEOF) if the FMODE_READ check is commented out in netfs_perform_write():\n\n                if (//(file->f_mode & FMODE_READ) ||\n                    netfs_is_cache_enabled(ctx)) {\n\nand no fscache.  This was initially found with the generic/522 xfstest.","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/4543a4d737944134a1394afe797622546fbcc98a","https://git.kernel.org/stable/c/5afc2d9b86bed2e4d9e1ba467790cbc793223f98","https://git.kernel.org/stable/c/5cd5207de519ef0c085f4f559adf5eefcb4c5202","https://git.kernel.org/stable/c/f706e3889ff75877ecb3abae5ad667dbc990331e"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-64159","score":0.00162,"percentile":0.05308,"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."]}