SB2026050274 - Improper Authentication in Linux kernel bluetooth

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Main Vulnerability Database SB2026050274

SB2026050274 - Improper Authentication in Linux kernel bluetooth

Published: May 2, 2026

Security Bulletin ID SB2026050274
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Adjecent network
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper Authentication (CVE-ID: CVE-2026-31773)

CWE-ID: CWE-287 - Improper Authentication

CVSSv4: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to bypass authentication requirements.

The vulnerability exists due to improper authentication state handling in the Bluetooth SMP legacy responder STK handling in smp_random() when processing Just Works or Confirm legacy pairing. A remote attacker can initiate a legacy pairing sequence that results in an unauthenticated STK being stored as authenticated to bypass authentication requirements.

The issue affects the legacy responder path and occurs when high security is requested but the pairing flow does not achieve MITM authentication.


Remediation

Install update from vendor's website.

References