Medium [CVE-2026-68405] Linux kernel: Wi-Fi subsystem vulnerability leads to system instability
This medium-severity Red Hat Linux advisory covers CVE-2026-68405 affecting Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9.
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Summary
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: free AP_VLAN bc_buf SKBs outside IRQ lock ieee80211_do_stop() removes AP_VLAN packets from the parent AP ps->bc_buf while holding ps->bc_buf.lock with IRQs disabled.
It then calls ieee80211_free_txskb() before dropping the lock. ieee80211_free_txskb() is not just a passive SKB release. For SKBs with TX status state it can report a dropped frame through cfg80211/nl80211, and that path can reach netlink tap transmit.
This is the same reason the pending queue cleanup in ieee80211_do_stop() already unlinks SKBs under the queue lock and frees them after IRQ state is restored.
The buggy scenario involves two paths, with each column showing the order within that path: AP_VLAN management TX: AP_VLAN stop: 1. attach ACK-status state 1. clear the running state 2. queue a multicast SKB on 2. take ps->bc_buf.lock with IRQs parent ps->bc_buf disabled 3. unlink the AP_VLAN SKB 4. call ieee80211_free_txskb() Unlink matching AP_VLAN SKBs from ps->bc_buf under the existing lock, but move them to a local free queue.
Drop the lock and restore IRQ state before calling ieee80211_free_txskb(). WARNING: kernel/softirq.c:430 at __local_bh_enable_ip When stopping an Access Point (AP) VLAN, the system attempts to free network packet buffers (SKBs) while interrupts are disabled.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
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