CVE-2026-63833

Public on 2026-07-19
Modified on 2026-07-24
Description
In the Linux kernel, the following vulnerability has been resolved:

ntfs3: reject direct userspace writes to reserved $LX* xattrs

NTFS3 uses $LXUID, $LXGID, $LXMOD and $LXDEV as internal WSL
permission metadata and reloads them into i_uid, i_gid and i_mode
from ntfs_get_wsl_perm().

Because the empty-prefix xattr handler also lets file owners call
setxattr() on these names directly, an unprivileged writer on a
writable ntfs3 mount can plant root ownership and S_ISUID on their own
file and gain euid 0 after inode reload.

Reject direct userspace writes to the reserved $LX* names. Internal
ntfs3 metadata updates are unchanged because ntfs_save_wsl_perm()
writes them via ntfs_set_ea() directly.

[almaz.alexandrovich@paragon-software.com: added an additional check for non privileged users]
Severity
Important severity
Important
See what this means
CVSS v3 Base Score
7.8
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 2 - Kernel-5.15 Extra kernel Pending Fix
Amazon Linux 2 - Core kernel Not Affected
Amazon Linux 2 - Kernel-5.10 Extra kernel Not Affected
Amazon Linux 2 - Kernel-5.4 Extra kernel Not Affected
Amazon Linux 2023 kernel Pending Fix
Amazon Linux 2023 kernel6.12 Pending Fix
Amazon Linux 2023 kernel6.18 Pending Fix

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H