# CVE-2026-63833: Linux Kernel privilege escalation in NTFS3 xattr handler

Source: https://junglewise.ai/threats/cve-2026-63833-linux-kernel-privilege-escalation-in-ntfs3-xattr-handler  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-19. Updated: 2026-07-19  
License: CC BY 4.0 with a link back

CVE-2026-63833 · Severity: info · CVSS 7.8 · Published 2026-07-19

A vulnerability in the Linux kernel's NTFS3 file system driver could allow a local user to gain administrative (root) privileges. By manually modifying hidden file attributes used for Windows Subsystem for Linux (WSL) compatibility, an unprivileged user can trick the system into granting them ownership of sensitive files. This could lead to a complete takeover of the affected system.

Technologies: [Linux Kernel](https://junglewise.ai/threats/technologies/kernel). Vendors: [Linux](https://junglewise.ai/threats/vendors/linux).

## Quick answers

**Is CVE-2026-63833 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-63833 being exploited in the wild.

**How severe is CVE-2026-63833?** Informational severity, with a CVSS score of 7.8, published 19 July 2026.

**Which products and versions are affected?** Linux Kernel 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3.

**Is there a fix for CVE-2026-63833?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-63833 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-63833?** Check whether you run Linux Kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A privilege escalation vulnerability exists in the Linux kernel ntfs3 driver due to improper validation of extended attributes (xattrs). The driver uses reserved xattrs ($LXUID, $LXGID, $LXMOD, and $LXDEV) to store WSL permission metadata, which are later reloaded into the inode's i_uid, i_gid, and i_mode. Because the empty-prefix xattr handler allowed file owners to call setxattr() on these reserved names directly, an unprivileged user could plant root ownership and the S_ISUID bit on a file they own. Upon inode reload, the attacker gains effective UID 0. The fix implements a check using ntfs_is_reserved_lxattr() to reject direct userspace writes to these attributes unless the caller has CAP_SYS_ADMIN.

## Affected products

- Linux Linux Kernel 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3

## Timeline

- 2026-06-10: other: Vulnerability fixed in source code by Konstantin Komarov
- 2026-07-19: disclosed: CVE published to the NVD

## References

- [https://git.kernel.org/stable/c/293a84fa40b3a1b3471c0545722724bc10973f76](https://git.kernel.org/stable/c/293a84fa40b3a1b3471c0545722724bc10973f76)
- [https://git.kernel.org/stable/c/2c3cd6da4a14380ef79e34bd9dff7caf46687477](https://git.kernel.org/stable/c/2c3cd6da4a14380ef79e34bd9dff7caf46687477)
- [https://git.kernel.org/stable/c/5b08dccecf825cbf905f348bc6ccb497507e28e2](https://git.kernel.org/stable/c/5b08dccecf825cbf905f348bc6ccb497507e28e2)
- [https://git.kernel.org/stable/c/5e658b9245a52d838ef93729a7bc07de8e19deb7](https://git.kernel.org/stable/c/5e658b9245a52d838ef93729a7bc07de8e19deb7)
- [https://git.kernel.org/stable/c/e574af95234afc3c725988bbc1fdeb46b9f386a4](https://git.kernel.org/stable/c/e574af95234afc3c725988bbc1fdeb46b9f386a4)
- [https://git.kernel.org/stable/c/e8852ae29868e449fdb47eebc28f35fb80741a5f](https://git.kernel.org/stable/c/e8852ae29868e449fdb47eebc28f35fb80741a5f)
- [https://git.kernel.org/stable/c/f8d420949b335a4b51d06ab276beee6b8dfdc909](https://git.kernel.org/stable/c/f8d420949b335a4b51d06ab276beee6b8dfdc909)

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