CVE-2026-64174: wifi: cfg80211: advance loop vars in cfg80211_merge_profile()

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

wifi: cfg80211: advance loop vars in cfg80211mergeprofile()

cfg80211mergeprofile() reassembles a Multi-BSSID non-transmitted BSS profile that has been split across multiple consecutive MBSSID elements. Its while-loop calls

cfg80211getprofilecontinuation(ie, ielen, mbssidelem, subelem)

but never advances mbssidelem or subelem inside the body. Each iteration therefore searches for a continuation that follows the same fixed pair; the helper returns the same nextmbssid; and the same nextsub bytes are memcpy()'d into mergedie at a growing offset until the buffer fills.

Advance both mbssidelem and subelem to the just-consumed continuation so the next call to cfg80211getprofilecontinuation() searches for a further continuation beyond it (or returns NULL when none exists).

A specially-crafted malicious beacon can take advantage of this bug to cause the kernel to spend an excessive amount of time in cfg80211mergeprofile (up to as much as 2ms per beacon received), which could theoretically be abused in some way.