CyberSecBulletin
CVE-2026-63833NVD status: Analyzed

Linux: Missing Authorization

Published Updated By the CyberSecBulletin desk

CVE-2026-63833 is a high-severity missing authorization vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions e574af95234afc3c725988bbc1fdeb46b9f386a4, 2c3cd6da4a14380ef79e34bd9dff7caf46687477, e8852ae29868e449fdb47eebc28f35fb80741a5f as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.14% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to e574af95234afc3c725988bbc1fdeb46b9f386a4 or 2c3cd6da4a14380ef79e34bd9dff7caf46687477 or e8852ae29868e449fdb47eebc28f35fb80741a5f or f8d420949b335a4b51d06ab276beee6b8dfdc909, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.15.211 or 6.1.177 or 6.6.144 or 6.12.95, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinuxbe71b5cba2e6485e8959da7a9f9a44461a1bb074 up to, but not including, e574af95234afc3c725988bbc1fdeb46b9f386a4; be71b5cba2e6485e8959da7a9f9a44461a1bb074 up to, but not including, 2c3cd6da4a14380ef79e34bd9dff7caf46687477; be71b5cba2e6485e8959da7a9f9a44461a1bb074 up to, but not including, e8852ae29868e449fdb47eebc28f35fb80741a5f; be71b5cba2e6485e8959da7a9f9a44461a1bb074 up to, but not including, f8d420949b335a4b51d06ab276beee6b8dfdc909; be71b5cba2e6485e8959da7a9f9a44461a1bb074 up to, but not including, 5e658b9245a52d838ef93729a7bc07de8e19deb7; be71b5cba2e6485e8959da7a9f9a44461a1bb074 up to, but not including, 293a84fa40b3a1b3471c0545722724bc10973f76; be71b5cba2e6485e8959da7a9f9a44461a1bb074 up to, but not including, 5b08dccecf825cbf905f348bc6ccb497507e28e2; 5.15e574af95234afc3c725988bbc1fdeb46b9f386a4, 2c3cd6da4a14380ef79e34bd9dff7caf46687477, e8852ae29868e449fdb47eebc28f35fb80741a5f, f8d420949b335a4b51d06ab276beee6b8dfdc909, 5e658b9245a52d838ef93729a7bc07de8e19deb7, 293a84fa40b3a1b3471c0545722724bc10973f76
LinuxLinux Kernel5.15 up to, but not including, 5.15.211; 5.16 up to, but not including, 6.1.177; 6.2 up to, but not including, 6.6.144; 6.7 up to, but not including, 6.12.95; 6.13 up to, but not including, 6.18.38; 6.19 up to, but not including, 7.1.35.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by CNA.

Official 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. [[email protected]: added an additional check for non privileged users]

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Missing Authorization

The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

How developers prevent this class of flaw

  • Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
  • Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework and the OWASP ESAPI Access Control feature.

More Missing Authorization vulnerabilities (CWE-862)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Missing Authorization vulnerabilities

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