CVE-2026-98183wifi: mac80211: avoid out-of-bounds read for empty PREQ elements

Official description

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: avoid out-of-bounds read for empty PREQ elements ieee80211_mesh_preq_size_ok() derives the location of the PREQ bottom fields before checking whether the element contains even the fixed header. ieee80211_mesh_hwmp_preq_get_bottom() reads the flags byte to account for the optional Address Extension field. Consequently, an empty PREQ element causes a one-byte read beyond its declared payload. Move the helper call after both size checks, so the bottom fields are only accessed when they are present.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/3beddbd56946577478fd5e649f556aaaebe15b0a
• https://git.kernel.org/stable/c/e6031f02269c0f51cf67886d177f02bc300b47cd