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]
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
See what this means
CVSS v3 Base Score
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 |