CVE-2026-63833 – ntfs3: reject direct userspace writes to reserved $LX* xattrs

CVE ID :CVE-2026-63833

Published : July 19, 2026, 12:16 p.m. | 1 hour, 23 minutes ago

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: 0.0 | NA

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