Bug 2555055 (CVE-2026-98703) - CVE-2026-98703 kernel: wifi: mac80211: minstrel_ht: validate fixed rate index
Summary: CVE-2026-98703 kernel: wifi: mac80211: minstrel_ht: validate fixed rate index
Keywords:
Status: NEW
Alias: CVE-2026-98703
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-18 15:51 UTC by OSIDB Bzimport
Modified: 2026-10-22 09:31 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2026-10-18 15:51:54 UTC
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.


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