CVE-2026-64388: smb/client: fix chown/chgrp with SMB3 POSIX Extensions
Greg Kroah-Hartman <[email protected]> Sat, 25 Jul 2026 10:50:05 +0200
| Newsgroups | org.kernel.vger.linux-cve-announce |
|---|---|
| Message-ID | <2026072527-CVE-2026-64388-82d9@gregkh> |
From: Greg Kroah-Hartman <[email protected]> Description =========== 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 CIFS_MOUNT_CIFS_ACL or CIFS_MOUNT_MODE_FROM_SID were also explicitly set. Fix this by checking for posix_extensions in cifs_setattr_nounix() when updating UID and GID, ensuring that id_mode_to_cifs_acl() is called to map and set the ownership/group information on the server. The Linux kernel CVE team has assigned CVE-2026-64388 to this issue. Affected and fixed versions =========================== Fixed in 7.1.4 with commit 550cfb8a81181331d4d0f76ab75ee58a0bf41e3e Fixed in 7.2-rc1 with commit 760ef2c579c2609cf17fb1cd5392f64d42d43d33 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-64388 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: fs/smb/client/inode.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3e https://git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33