CyberSecBulletin
CVE-2026-43334NVD status: Modified

Linux: Incorrect Authorization

Published Updated By the CyberSecBulletin desk

CVE-2026-43334 is a high-severity incorrect authorization vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions 425a22c5373d4e1b46492ab869074ebeeade61f3, 7ab69426e7ecbd18a222ee2ec87ca612d30197d7, 01bb4045d2306c266178f49ce0c3576d237a3040 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 0.28% 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 425a22c5373d4e1b46492ab869074ebeeade61f3 or 7ab69426e7ecbd18a222ee2ec87ca612d30197d7 or 01bb4045d2306c266178f49ce0c3576d237a3040 or 91649c02c1baaa18cedf7fb425fa1f0f852c8183, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.168 or 6.6.134, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux2b64d153a0cc9d2b60e47be013cde8490f16e0a5 up to, but not including, 425a22c5373d4e1b46492ab869074ebeeade61f3; 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 up to, but not including, 7ab69426e7ecbd18a222ee2ec87ca612d30197d7; 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 up to, but not including, 01bb4045d2306c266178f49ce0c3576d237a3040; 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 up to, but not including, 91649c02c1baaa18cedf7fb425fa1f0f852c8183; 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 up to, but not including, c8ff0ca6508535bccabd81c5c9dcc63de8a3d4fb; 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 up to, but not including, fa14e0e19820b1bbdb42185c9c4efa950bcffef9; 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 up to, but not including, ec17efb1ef91506cfd17a77692eaf4bbacb520ea; 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 up to, but not including, d05111bfe37bfd8bd4d2dfe6675d6bdeef43f7c7; and 1 more ranges425a22c5373d4e1b46492ab869074ebeeade61f3, 7ab69426e7ecbd18a222ee2ec87ca612d30197d7, 01bb4045d2306c266178f49ce0c3576d237a3040, 91649c02c1baaa18cedf7fb425fa1f0f852c8183, c8ff0ca6508535bccabd81c5c9dcc63de8a3d4fb, fa14e0e19820b1bbdb42185c9c4efa950bcffef9
LinuxLinux Kernel3.3 up to, but not including, 5.10.253; 5.11 up to, but not including, 5.15.203; 5.16 up to, but not including, 6.1.168; 6.2 up to, but not including, 6.6.134; 6.7 up to, but not including, 6.12.81; 6.13 up to, but not including, 6.18.22; 6.19 up to, but not including, 6.19.12; 7.05.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22

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
AdjacentThe attacker must be on the same local network segment.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
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
HighThe component can be taken down completely.

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

Official description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: SMP: force responder MITM requirements before building the pairing response smp_cmd_pairing_req() currently builds the pairing response from the initiator auth_req before enforcing the local BT_SECURITY_HIGH requirement. If the initiator omits SMP_AUTH_MITM, the response can also omit it even though the local side still requires MITM. tk_request() then sees an auth value without SMP_AUTH_MITM and may select JUST_CFM, making method selection inconsistent with the pairing policy the responder already enforces. When the local side requires HIGH security, first verify that MITM can be achieved from the IO capabilities and then force SMP_AUTH_MITM in the response in both rsp.auth_req and auth. This keeps the responder auth bits and later method selection aligned.

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: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Incorrect Authorization vulnerabilities

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