CVE-2026-68406 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: validate PMSR FTM preamble range
PMSR FTM request parsing accepts preamble values outside the enumerated nl80211 preamble range.
Reject out-of-range values before using them in the parser capability bit test using the policy.
[drop unnecessary check]
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 08/10/2026
The vulnerability resides within the linux kernel's wireless subsystem, specifically in the cfg80211 component responsible for managing wireless configuration and management. This issue affects the parsing of Peer Measurement Service Request (PMSR) Fast Time Measurement (FTM) requests which are part of the 802.11 standard for measuring distances between wireless devices. The flaw manifests when processing FTM request parameters, particularly the preamble field that defines the transmission format used in time measurement calculations.
The technical implementation defect occurs during input validation where the kernel fails to properly validate preamble values against the defined nl80211 enumeration ranges before proceeding with subsequent parsing operations. This allows malicious actors to submit FTM requests containing preamble values that exceed the legitimate range specified by the wireless standards. The vulnerability stems from inadequate boundary checking in the configuration parsing logic, where out-of-range values are accepted and processed without proper validation.
When an attacker submits a malformed FTM request with invalid preamble values, the kernel's parser continues processing these values and performs capability bit tests using the invalid data. This can lead to unpredictable behavior including potential memory corruption, denial of service conditions, or in worst-case scenarios, privilege escalation attacks that could compromise the entire wireless subsystem. The operational impact extends beyond simple service disruption as it affects the fundamental integrity of wireless communication management within kernel space.
This vulnerability aligns with CWE-129 Input Validation and CWE-704 Incorrect Calculation, specifically targeting improper validation of wireless protocol parameters. From an attack perspective, this flaw maps to techniques described in the ATT&CK framework under T1547.006 System Service Execution and T1068 Local Privilege Escalation, as it could enable attackers to manipulate kernel-level wireless operations. The fix implemented involves adding proper validation checks before any capability bit testing occurs, ensuring that preamble values conform to the defined nl80211 ranges before processing.
The resolution addresses the core issue by incorporating defensive programming practices that validate input parameters against established enumerations prior to any operational processing. This change prevents out-of-range values from reaching the capability bit test logic and eliminates potential vectors for exploitation. The fix represents a standard security hardening approach that aligns with kernel security best practices and reduces the attack surface for wireless subsystem vulnerabilities.
Security implications extend to enterprise wireless networks where this vulnerability could be exploited to disrupt critical communication services or potentially gain unauthorized access to network management functions. The remediation ensures that wireless configuration parameters are properly validated before being used in kernel space operations, maintaining system integrity and preventing potential escalation paths that could compromise overall network security posture.