CVE-2026-98703wifi: mac80211: minstrel_ht: validate fixed rate index

Official description

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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/63097bf1b7f17f14bd9ffcae6590c63272da8bb0
• https://git.kernel.org/stable/c/9b685cfb5cc8ed57991b1a956b06c6658d7cf455
• https://git.kernel.org/stable/c/eebc70f132041b35da9ec74d5d395083125289b2
• https://git.kernel.org/stable/c/f8ab6ae1fa360b0191252677f41e781dcb0ffe6e
• https://git.kernel.org/stable/c/42aa9feb27b600809414a3c6b0c650bafba542a9
• https://git.kernel.org/stable/c/43082d604a9937b94ceb2e484403956d0f363324
• https://git.kernel.org/stable/c/15fb9e3cea55fbc378261ce35a32b0f8828f0000