CVE-2026-98703

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

wifi: mac80211: minstrel_ht: validate fixed rate index

The fixed_rate_idx debugfs file is a plain u32 attribute, so any value

can be written to it. minstrel_ht_update_stats() then copies the value

into mi->max_tp_rate[] and mi->max_prob_rate, and

minstrel_ht_set_rate() uses MI_RATE_GROUP()/MI_RATE_IDX() to index

minstrel_mcs_groups[] (42 entries) and mi->groups[].rates[] (10 entries)

with it.

Writing e.g. 65535 selects group 4095 and rate index 15, far outside

both arrays. The out-of-bounds entries are dereferenced and updated as

struct minstrel_rate_stats (retry counts, etc.), so the invalid index

corrupts adjacent kernel memory. With CONFIG_UBSAN_BOUNDS the access is

reported as an array-index-out-of-bounds in minstrel_ht_set_rate().

Only a valid group/rate pair, or U32_MAX to disable fixed rate

processing, can be used safely, so reject any other value when the

debugfs file is written.

The file is only reachable through a root-only debugfs mount, so this is

not a privilege boundary. The out-of-bounds access is still a bug that

must not be reachable through a writable debugfs attribute.