CVE-2026-68405: Linux kernel · wifi: mac80211: free AP_VLAN bc_buf SKBs outside IRQ lock
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in f3858d5b1432098c1936e03d6e03dd0e33facf60 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 17:04 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in f3858d5b1432098c1936e03d6e03dd0e33facf60, be9dfcb0654c1f6c0fce7ba2a909683bb6f1e0ef, aa01ef0ebbc3289154229ef58e65baf289eb9789 +5
Exploitation evidence
Disclosed: evidence found.
CVE published 10 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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Description
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
References
- git.kernel.org/stable/c/0d2619e708e2ef02ba1c91642ea261d3f19d8f9a (opens in a new tab)
- git.kernel.org/stable/c/659a81b62a61440b85e02c09903be861ae7679e5 (opens in a new tab)
- git.kernel.org/stable/c/aa01ef0ebbc3289154229ef58e65baf289eb9789 (opens in a new tab)
- git.kernel.org/stable/c/be9dfcb0654c1f6c0fce7ba2a909683bb6f1e0ef (opens in a new tab)
- git.kernel.org/stable/c/962f755a47d7ec3bbf6c709697d7f4c5f798441d (opens in a new tab)
- git.kernel.org/stable/c/a424985c3ef2a87ce6057a853e18d0c441a86be8 (opens in a new tab)
- git.kernel.org/stable/c/4b8abf43bf34791c99d99dc3be13f897adefc461 (opens in a new tab)
- git.kernel.org/stable/c/f3858d5b1432098c1936e03d6e03dd0e33facf60 (opens in a new tab)