CVE-2026-63833
Published: July 22, 2026Last modified: July 22, 2026
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. [[email protected]: added an additional check for non privileged users]
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.1 |
| Attack Vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | HIGH |
| Availability impact | NONE |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Fixed (6.1.177-r0) |
| 25 LTS | linux-lts | Fixed (6.12.95-r0) | |
| Stream | linux-lts | Fixed (6.18.38-r0) |
References
- https://git.kernel.org/stable/c/293a84fa40b3a1b3471c0545722724bc10973f76
- https://git.kernel.org/stable/c/2c3cd6da4a14380ef79e34bd9dff7caf46687477
- https://git.kernel.org/stable/c/5b08dccecf825cbf905f348bc6ccb497507e28e2
- https://git.kernel.org/stable/c/5e658b9245a52d838ef93729a7bc07de8e19deb7
- https://git.kernel.org/stable/c/e574af95234afc3c725988bbc1fdeb46b9f386a4
- https://git.kernel.org/stable/c/e8852ae29868e449fdb47eebc28f35fb80741a5f
- https://git.kernel.org/stable/c/f8d420949b335a4b51d06ab276beee6b8dfdc909