UBUNTU-CVE-2026-98887: Medium severity ubuntu/linux vulnerability

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211hwsim: reject undersized HWSIMATTRTXINFO hwsimtxinfoframereceivednl() casts the HWSIMATTRTXINFO payload to a struct hwsimtxrate and unconditionally reads IEEE80211TXMAXRATES entries (8 bytes) from it. The policy only bounds the attribute from above (NLABINARY .len is a maximum) and the op sets GENLDONTVALIDATESTRICT, so a short or zero-length attribute is accepted and the loop reads past the payload. Require the exact length in the policy, so a malformed attribute is rejected before the handler runs.