{"cve":"CVE-2026-64388","nvd":{"published":"2026-07-25T10:17:22.127","modified":"2026-10-21T13:19:22.980","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb/client: fix chown/chgrp with SMB3 POSIX Extensions\n\nOwnership (chown) and group (chgrp) modifications were being ignored when\nmounting with SMB3 POSIX Extensions unless CIFS_MOUNT_CIFS_ACL or\nCIFS_MOUNT_MODE_FROM_SID were also explicitly set.\n\nFix this by checking for posix_extensions in cifs_setattr_nounix() when\nupdating UID and GID, ensuring that id_mode_to_cifs_acl() is called to map\nand set the ownership/group information on the server.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-682"],"references":["https://git.kernel.org/stable/c/27ead8c5418af6bfab711079fecb9414d78d4cae","https://git.kernel.org/stable/c/3eaec47518e126e6dcd1a48521d740278073f0ec","https://git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3e","https://git.kernel.org/stable/c/6825a45f6b8ef76b0ee32649ec3d6e39ca143a18","https://git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-64388","score":0.00133,"percentile":0.02843,"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."]}