# CVE-2026-63833: ntfs3: reject direct userspace writes to reserved $LX* xattrs

CVE-2026-63833 is fixed in 56 products on 1 platform, first by ALAS2023-2026-1969, released July 20, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-63833
- Priority: Urgent
- CVSS: 9.8 (Critical)
- EPSS: 0.0014
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 19, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-63833

## 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]

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bpftool amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | bpftool-debuginfo amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | bpftool6.12 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | bpftool6.12-debuginfo amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | bpftool6.18 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-debuginfo amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-debuginfo-common-aarch64 amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-debuginfo-common-x86_64 amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-devel amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-headers amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-livepatch-6.1.177-224.371 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-livepatch-6.12.95-124.187 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel-livepatch-6.18.38-73.137 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel-modules-extra amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-modules-extra-common amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-tools amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-tools-debuginfo amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel-tools-devel amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | kernel6.12 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.12-debuginfo amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.12-debuginfo-common-aarch64 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.12-debuginfo-common-x86_64 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.12-devel amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.12-headers amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.12-modules-extra amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.12-modules-extra-common amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.12-tools amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.12-tools-debuginfo amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.12-tools-devel amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | kernel6.18 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel6.18-devel amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel6.18-headers amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel6.18-tools amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | linux Debian 12.15 (bookworm) | 6.1.177-1 | [DEBIAN-CVE-2026-63833](https://patchblox.com/security/data/fix/linux/debian-cve-2026-63833.md) | Jul 20, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.95-1 | [DEBIAN-CVE-2026-63833](https://patchblox.com/security/data/fix/linux/debian-cve-2026-63833.md) | Jul 20, 2026 |
| Linux | linux Debian 14 | 7.1.3-1 | [DEBIAN-CVE-2026-63833](https://patchblox.com/security/data/fix/linux/debian-cve-2026-63833.md) | Jul 20, 2026 |
| Linux | microvm-kernel6.18 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | perf amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | perf-debuginfo amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | perf6.12 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | perf6.12-debuginfo amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | perf6.18 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | python3-perf amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | python3-perf-debuginfo amzn 2023 | 1:6.1.177-224.371.amzn2023 | [ALAS2023-2026-2032](https://patchblox.com/security/data/fix/linux/alas2023-2026-2032.md) | Aug 3, 2026 |
| Linux | python3-perf6.12 amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | python3-perf6.12-debuginfo amzn 2023 | 1:6.12.95-124.187.amzn2023 | [ALAS2023-2026-2014](https://patchblox.com/security/data/fix/linux/alas2023-2026-2014.md) | Aug 3, 2026 |
| Linux | python3-perf6.18 amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |
| Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.38-73.137.amzn2023 | [ALAS2023-2026-1969](https://patchblox.com/security/data/fix/linux/alas2023-2026-1969.md) | Jul 20, 2026 |

---

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