CVE-2026-98422

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

wifi: mac80211: reset the AP VLAN tailroom counter on ifdown

On ifup, AP VLAN interfaces get crypto tx tailroom needed cnt from the AP interface, but it's never decremented again unless the AP is also brought down. Thus, bringing the same AP VLAN up again will increment the counter again and eventually hit the sanity check:

WARN ON ONCE(sdata->crypto tx tailroom needed cnt != master->crypto tx tailroom needed cnt);

Reset it on ifdown to avoid that.