{"id":"CVE-2026-64388","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-64388","generatedAt":"2026-10-28T07:04:43.367Z","title":"In the Linux kernel, the following vulnerability has been resolved: smb/client: fix chown/chgrp with SMB3 POSIX Extensions Ownership (chown) and group (chgrp) modifications were being ignored when mounting with SMB3 POSIX Extensions unless…","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.","published":"2026-07-25T10:17:22.000Z","lastModified":"2026-10-21T13:19:23.000Z","status":"Modified","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-682"],"affected":["linux/linux kernel"],"epss":{"score":0.00133,"percentile":0.02846,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.13%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/27ead8c5418af6bfab711079fecb9414d78d4cae","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3eaec47518e126e6dcd1a48521d740278073f0ec","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3e","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6825a45f6b8ef76b0ee32649ec3d6e39ca143a18","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64388","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}