CVE-2026-68407 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: nl80211: free RNR data on MBSSID mismatch
nl80211_parse_beacon() rejects EMA RNR data when there are fewer RNR entries than MBSSID entries.
The rejected RNR allocation has not been attached to the beacon data yet, so free it before returning the error.
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Analysis
by VulDB Data Team • 08/10/2026
This vulnerability resides within the linux kernel's wireless subsystem, specifically in the nl80211 subsystem responsible for managing wireless network configurations. The issue manifests during beacon frame processing where the system encounters a mismatch between multiple BSSID (MBSSID) entries and enhanced measurement advertisement (EMA) RNR (Radio Network Information) data entries. When the nl80211_parse_beacon() function detects that RNR entries are fewer than MBSSID entries, it appropriately rejects the EMA RNR data but fails to properly handle memory management.
The technical flaw represents a memory leak condition occurring in the wireless beacon parsing routine. When the function identifies an MBSSID mismatch with RNR data, it correctly determines that the EMA RNR allocation should be rejected and returns an error status. However, the allocated memory for the rejected RNR data remains unfreed, creating a resource leak that persists until the system reboots or the wireless subsystem is reset. This condition violates standard memory management practices and can accumulate over time, potentially leading to system instability.
The operational impact of this vulnerability extends beyond simple memory consumption issues. While the immediate effect may appear minor, sustained memory leaks in kernel space can progressively degrade system performance and stability. In wireless access point scenarios, where beacon frames are continuously processed, this leak could compound over time and affect network reliability. The vulnerability affects wireless devices operating in 802.11 environments, particularly those implementing multiple BSSID configurations for load balancing or network segmentation purposes.
Security implications of this memory leak vulnerability align with CWE-401, which categorizes improper resource management as a common weakness leading to denial of service conditions. The issue also relates to ATT&CK technique T1499.003, which addresses resource consumption attacks that can lead to system instability through memory exhaustion. Proper mitigation involves ensuring all allocated memory is properly freed before function returns, regardless of error conditions. The fix requires modifying the nl80211_parse_beacon() function to include explicit memory deallocation for rejected RNR data before returning error codes.
This vulnerability demonstrates the critical importance of proper resource management in kernel space operations where memory leaks can have cascading effects on system stability and performance. The fix ensures that all allocated memory is properly accounted for and freed, preventing accumulation of leaked resources that could eventually impact wireless network operations or overall system functionality. The resolution addresses a fundamental programming error where error handling paths fail to clean up allocated resources, a pattern commonly identified in kernel security audits and vulnerability assessments.