Local root escalation via writable reserved xattrs
Published Jul 19, 2026 · Updated Jul 19, 2026
Privilege escalation in the Linux kernel NTFS3 driver allows local users to gain effective UID 0 through a writable NTFS3 mount. The empty-prefix xattr handler permits file owners to write reserved $LXUID, $LXGID, $LXMOD, and $LXDEV metadata that ntfs_get_wsl_perm() trusts when restoring inode ownership and mode. Write access to an owned file on a writable NTFS3 mount is sufficient to plant root ownership and S_ISUID, then execute the file as root after inode reload.
Summary
What happened
Privilege escalation in the Linux kernel NTFS3 driver allows local users to gain effective UID 0 through a writable NTFS3 mount. The empty-prefix xattr handler permits file owners to write reserved $LXUID, $LXGID, $LXMOD, and $LXDEV metadata that ntfs_get_wsl_perm() trusts when restoring inode ownership and mode. Write access to an owned file on a writable NTFS3 mount is sufficient to plant root ownership and S_ISUID, then execute the file as root after inode reload.
The record
- CVE
- CVE-2026-63833
- Published
- Jul 19, 2026
- Updated
- Jul 19, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 19, 2026CVE publishedPublication date reported by the CVE source.
- Jul 19, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <5.15.211
- Affected versionversion=0 <6.1.177
- Affected versionversion=0 <6.12.95
- Affected versionversion=0 <6.18.38
- Affected versionversion=0 <6.6.144
- Affected versionversion=0 <7.1.3
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <293a84fa40b3a1b3471c0545722724bc10973f76
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <2c3cd6da4a14380ef79e34bd9dff7caf46687477
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5b08dccecf825cbf905f348bc6ccb497507e28e2
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5e658b9245a52d838ef93729a7bc07de8e19deb7
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e574af95234afc3c725988bbc1fdeb46b9f386a4
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e8852ae29868e449fdb47eebc28f35fb80741a5f
- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f8d420949b335a4b51d06ab276beee6b8dfdc909
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo