wifi: mac80211: Fix static_branch_dec() underflow for aql_di…(CVE-2026-31551)

概要

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable.

原文の説明

取得元が公開している説明をそのまま載せています (多くは英語)。

In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: Fix static_branch_dec() underflow for aql_disable.

syzbot reported static_branch_dec() underflow in aql_enable_write(). [0]

The problem is that aql_enable_write() does not serialise concurrent
write()s to the debugfs.

aql_enable_write() checks static_key_false(&aql_disable.key) and
later calls static_branch_inc() or static_branch_dec(), but the
state may change between the two calls.

aql_disable does not need to track inc/dec.

Let's use static_branch_enable() and static_branch_disable().

[0]:
val == 0
WARNING: kernel/jump_label.c:311 at __static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311, CPU#0: syz.1.3155/20288
Modules linked in:
CPU: 0 UID: 0 PID: 20288 Comm: syz.1.3155 Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__static_key_slow_dec_cpuslocked.part.0+0x107/0x120 kernel/jump_label.c:311
Code: f2 c9 ff 5b 5d c3 cc cc cc cc e8 54 f2 c9 ff 48 89 df e8 ac f9 ff ff eb ad e8 45 f2 c9 ff 90 0f 0b 90 eb a2 e8 3a f2 c9 ff 90 <0f> 0b 90 eb 97 48 89 df e8 5c 4b 33 00 e9 36 ff ff ff 0f 1f 80 00
RSP: 0018:ffffc9000b9f7c10 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffffff9b3e5d40 RCX: ffffffff823c57b4
RDX: ffff8880285a0000 RSI: ffffffff823c5846 RDI: ffff8880285a0000
RBP: 0000000000000000 R08: 0000000000000005 R09: 000000000000…

出典: OSV.dev (Open Source Vulnerabilities) NVD OSV

影響パッケージ

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"5.12.0"},{"fixed":"5.15.203"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.167"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.130"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.78"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.20"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.10"}]}]

ディストリビューション別の修正状況

各ディストリビューションが公開している、この CVE の修正パッケージ

BellSoft Alpaquita BELL-CVE-2026-31551 linux-lts 修正版: 6.1.167-r0
Debian DEBIAN-CVE-2026-31551 linux 修正版: 6.1.170-1
Ubuntu UBUNTU-CVE-2026-31551 linux-hwe-edge

概要

原文の説明

影響パッケージ

ディストリビューション別の修正状況

参照URL