CVE-2026-93804 Linux CVE debrief

Who should care

Linux kernel maintainers, Linux distribution vendors, and users of Linux-based systems, especially those using wireless networking, should assess exposure and apply patches or updates as needed.

Why it matters

A race condition vulnerability in the Linux kernel's mac80211 IBSS disconnect handling could lead to drivers receiving invalid queue requests, potentially causing system instability or crashes.

• Verify Linux kernel versions and configurations for exposure
• Apply patches or updates provided by the Linux kernel maintainers
• Monitor system logs for potential indicators of compromise

Technical summary

The Linux kernel's mac80211 IBSS disconnect handling has a race condition vulnerability. When leaving an IBSS, mac80211 flushes stations, turns the carrier off, and tells the driver to leave. However, due to cross-CPU race conditions, packets can still be transmitted after the carrier is turned off. This can cause drivers to receive invalid queue requests, leading to potential issues. The fix involves moving the netif_carrier_off() operation before sta_info_flush() and adding synchronize_net() if flushing didn't occur.

Defensive priority

Medium

Recommended defensive actions

• Review Linux kernel versions and configurations for exposure
• Apply patches or updates provided by the Linux kernel maintainers
• Monitor system logs for potential indicators of compromise
• Verify driver functionality and queue management
• Perform an inventory of assets using Linux-based systems, especially those using wireless networking
• Establish a rollback plan for changes made to remediate this vulnerability
• Track and verify the effectiveness of applied patches or updates

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, but the scope of affected systems and versions is not explicitly stated. The Linux kernel patch commits are referenced, indicating that the fix is available.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.