CVE-2026-63833

Summary

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]

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxbe71b5cba2e6485e8959da7a9f9a44461a1bb074 < e574af95234afc3c725988bbc1fdeb46b9f386a4affected
LinuxLinuxbe71b5cba2e6485e8959da7a9f9a44461a1bb074 < 2c3cd6da4a14380ef79e34bd9dff7caf46687477affected
LinuxLinuxbe71b5cba2e6485e8959da7a9f9a44461a1bb074 < e8852ae29868e449fdb47eebc28f35fb80741a5faffected
LinuxLinuxbe71b5cba2e6485e8959da7a9f9a44461a1bb074 < f8d420949b335a4b51d06ab276beee6b8dfdc909affected
LinuxLinuxbe71b5cba2e6485e8959da7a9f9a44461a1bb074 < 5e658b9245a52d838ef93729a7bc07de8e19deb7affected
LinuxLinuxbe71b5cba2e6485e8959da7a9f9a44461a1bb074 < 293a84fa40b3a1b3471c0545722724bc10973f76affected
LinuxLinuxbe71b5cba2e6485e8959da7a9f9a44461a1bb074 < 5b08dccecf825cbf905f348bc6ccb497507e28e2affected
LinuxLinux5.15affected
LinuxLinux0 < 5.15unaffected
LinuxLinux5.15.211 <= 5.15.*unaffected
LinuxLinux6.1.177 <= 6.1.*unaffected
LinuxLinux6.6.144 <= 6.6.*unaffected
LinuxLinux6.12.95 <= 6.12.*unaffected
LinuxLinux6.18.38 <= 6.18.*unaffected
LinuxLinux7.1.3 <= 7.1.*unaffected
LinuxLinux7.2-rc1 <= *unaffected

Weaknesses

References