Vulnerability in Linux

CVE-2026-63833

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]

EPSS: 0.001 (2.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.

Affected products

  • Linux — versions 6.18.38, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 7.2-rc1

References

Frequently asked questions

What is CVE-2026-63833?
CVE-2026-63833 is a high-severity vulnerability in Linux. CVSS score: 7.1/10. Published 2026-07-19.
How severe is CVE-2026-63833?
High severity. CVSS v3 base score is 7.1 out of 10.