In plain language
What this advisory means
A serious security flaw was found in the wifi management component of the Azure Linux 3.0 kernel version 6.6.157.1-1. This flaw happens because the system mistakenly ignores certain checks when cleaning up old wifi records. This can cause security problems. Microsoft has released an update to fix this problem. Users of this Azure Linux version should update their systems as soon as possible.
Technical explanation
How the issue affects the environment
The vulnerability, identified as CVE-2026-98339, involves the cfg80211 subsystem within the wifi stack of the Linux kernel shipped with Azure Linux 3.0, specifically version 6.6.157.1-1. The issue occurs because the kernel improperly filters stale entries by their BSS (Basic Service Set) type when removing them, potentially leading to incorrect removal and impacting wifi management integrity. This flaw is addressed in the updated kernel version 6.6.158.1-1, which removes the incorrect filter to handle stale entries properly.
Operational impact
Why teams should care
If exploited, this vulnerability could compromise wifi network handling, potentially allowing attackers to disrupt wireless communications or evade detection. This can impact the security and reliability of systems running the vulnerable Azure Linux 3.0 kernel, leading to operational risks and possible data exposure.
Immediate action
Users should upgrade the Azure Linux 3.0 kernel from version 6.6.157.1-1 to version 6.6.158.1-1 or later, as documented in the Microsoft Security Update Guide and upgrade tutorials.
Affected and fixed releases
Temporary risk reduction
No separate workaround was supplied in the source feed. Use the official vendor advisory before changing production controls.
Evidence and validation checklist
- Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2026-98339
- Microsoft documentation states fix is in version 6.6.158.1-1 for azl3 kernel on Azure Linux 3.0.
- Summary highlights kernel wifi cfg80211 stale entry filtering change.
- No public details or exploitation reports provided in advisory.
Authoritative reference
Microsoft Security Response Center
QCS detected and normalized this record from the official source. Vendor guidance remains authoritative.