CyberSecBulletin
CVE-2026-46076NVD status: Undergoing Analysis

Linux: Incorrect Authorization

Published Updated By the CyberSecBulletin desk

CVE-2026-46076 is a high-severity incorrect authorization vulnerability in Linux, with a CVSS 3.1 base score of 7.9 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 fcef67506c0234935cb0fb026740a637edb58d7c, 924d721fae95687acedbaf624a094ed0e8b67104, 009c0f726abeaa67aad1d96b883bdce01d405ce2 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 fcef67506c0234935cb0fb026740a637edb58d7c or 924d721fae95687acedbaf624a094ed0e8b67104 or 009c0f726abeaa67aad1d96b883bdce01d405ce2 or 5fb4a5f361565f5b629d8a8fe5288ce8463c5727, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.12.86 or 6.18.27 or 7.0.4, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 up to, but not including, fcef67506c0234935cb0fb026740a637edb58d7c; 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 up to, but not including, 924d721fae95687acedbaf624a094ed0e8b67104; 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 up to, but not including, 009c0f726abeaa67aad1d96b883bdce01d405ce2; 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 up to, but not including, 5fb4a5f361565f5b629d8a8fe5288ce8463c5727; 3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 up to, but not including, c36991c6f8d2ab56ee67aff04e3c357f45cfc76c; 6.2fcef67506c0234935cb0fb026740a637edb58d7c, 924d721fae95687acedbaf624a094ed0e8b67104, 009c0f726abeaa67aad1d96b883bdce01d405ce2, 5fb4a5f361565f5b629d8a8fe5288ce8463c5727, c36991c6f8d2ab56ee67aff04e3c357f45cfc76c
LinuxLinux Kernel6.2 up to, but not including, 6.12.86; 6.13 up to, but not including, 6.18.27; 6.19 up to, but not including, 7.0.46.12.86, 6.18.27, 7.0.4

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
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
LowSome restricted data can be read.
Integrity
LowLimited modification of data is possible.
Availability
HighThe component can be taken down completely.

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

Official description

In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Raise #UD if unhandled VMMCALL isn't intercepted by L1 Explicitly synthesize a #UD for VMMCALL if L2 is active, L1 does NOT want to intercept VMMCALL, nested_svm_l2_tlb_flush_enabled() is true, and the hypercall is something other than one of the supported Hyper-V hypercalls. When all of the above conditions are met, KVM will intercept VMMCALL but never forward it to L1, i.e. will let L2 make hypercalls as if it were L1. The TLFS says a whole lot of nothing about this scenario, so go with the architectural behavior, which says that VMMCALL #UDs if it's not intercepted. Opportunistically do a 2-for-1 stub trade by stub-ifying the new API instead of the helpers it uses. The last remaining "single" stub will soon be dropped as well. [sean: rewrite changelog and comment, tag for stable, remove defunct stubs]

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

The underlying weakness: Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

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 Incorrect Authorization vulnerabilities (CWE-863)

Timeline

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

References

Recent Incorrect Authorization vulnerabilities

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