CVE-2026-63833

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

State: Published
Severity: 7.1 High
Published: Jul 19, 2026
Updated: Oct 19, 2026
Reserved: Jul 19, 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.

[almaz.alexandrovich@paragon-software.com: added an additional check for non privileged users]

Scores

CVSS	Score	Vector	Source
3.1	7.1 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N	Linux

Weaknesses

CWE-862 Missing Authorization

Affected Products

Product	Versions
LinuxLinux	be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before e574af95234afc3c725988bbc1fdeb46b9f386a4Affected be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before 2c3cd6da4a14380ef79e34bd9dff7caf46687477Affected be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before e8852ae29868e449fdb47eebc28f35fb80741a5fAffected be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before f8d420949b335a4b51d06ab276beee6b8dfdc909Affected be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before 5e658b9245a52d838ef93729a7bc07de8e19deb7Affected be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before 293a84fa40b3a1b3471c0545722724bc10973f76Affected be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before 5b08dccecf825cbf905f348bc6ccb497507e28e2Affected
LinuxLinux	5.15Affected before 5.15Not affected 5.15.211 through 5.15.Not affected 6.1.177 through 6.1.Not affected 6.6.144 through 6.6.Not affected 6.12.95 through 6.12.Not affected 6.18.38 through 6.18.Not affected 7.1.3 through 7.1.Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before e574af95234afc3c725988bbc1fdeb46b9f386a4Affected
be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before 2c3cd6da4a14380ef79e34bd9dff7caf46687477Affected
be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before e8852ae29868e449fdb47eebc28f35fb80741a5fAffected
be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before f8d420949b335a4b51d06ab276beee6b8dfdc909Affected
be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before 5e658b9245a52d838ef93729a7bc07de8e19deb7Affected
be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before 293a84fa40b3a1b3471c0545722724bc10973f76Affected
be71b5cba2e6485e8959da7a9f9a44461a1bb074 to before 5b08dccecf825cbf905f348bc6ccb497507e28e2Affected

LinuxLinux

5.15Affected
before 5.15Not affected
5.15.211 through 5.15.*Not affected
6.1.177 through 6.1.*Not affected
6.6.144 through 6.6.*Not affected
6.12.95 through 6.12.*Not affected
6.18.38 through 6.18.*Not affected
7.1.3 through 7.1.*Not affected
7.2 and laterNot affected

References

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