In plain language
What this advisory means
A vulnerability in the Wi-Fi handling code of the Azure Linux 3.0 kernel could cause unsafe memory access. This issue relates to how some network data statistics are freed in the system, potentially affecting system stability or security. Users of Azure Linux 3.0 should check Microsoft's update guide to determine if they need to update or take other security measures.
Technical explanation
How the issue affects the environment
The vulnerability involves the mac80211 wireless subsystem in the Linux kernel version 6.6.150.1-1 on Azure Linux 3.0. Specifically, the freeing of per-CPU (per processor) data structures storing link receive (RX) statistics is not properly deferred using the Read-Copy-Update (RCU) synchronization mechanism. Without deferring the free operation to RCU, other parts of the kernel might access freed memory concurrently, leading to use-after-free issues which can cause data corruption or crashes. Deferring memory release via RCU is essential in concurrent environments to maintain data consistency and system reliability.
Operational impact
Why teams should care
If exploited, this vulnerability might lead to system instability or security compromises by causing kernel crashes or exposing memory access flaws. This scenario could affect the uptime and trustworthiness of Azure Linux 3.0 systems running on azl3 kernel 6.6.150.1-1, possibly impacting business operations reliant on these systems. Organizations should evaluate their exposure and apply appropriate mitigation steps to preserve service continuity.
Immediate action
Microsoft recommends reviewing the Microsoft Security Update Guide for applicability and steps for remediation. Users should consult the Azure Linux upgrade tutorial to apply any available updates or mitigation measures as provided by Microsoft.
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 confirming the vulnerability and severity.
- Specific mention of mac80211 subsystem and deferral of link RX stats per-CPU free to RCU.
- Listing of affected product: azl3 kernel 6.6.150.1-1 on Azure Linux 3.0.
- References to Microsoft Security Update Guide for remediation guidance.
Authoritative reference
Microsoft Security Response Center
QCS detected and normalized this record from the official source. Vendor guidance remains authoritative.