CVE-2026-80934EPSS p9.7%
CVE-2026-80934CVE-2026-80934
Description
In the Linux kernel, the following vulnerability has been resolved:
wifi: mt76: mt7996: fix TX DMA mapping leak for AddBA req frames
mt7996/mt7992 hand the firmware a HW MAC-TXP for AddBA req action frames
(MT_TXD7_MAC_TXD, set in mt7996_mac_write_txwi_80211()), but are otherwise
FW-TXP devices. On tx free mt76_connac_txp_skb_unmap() therefore decodes
the per-frame txp as a struct mt76_connac_fw_txp. For a MAC-TXP the
fw_txp.nbuf byte aliases the AddBA TID word (MT_TXP1_TID_ADDBA), which is
always zero, so the unmap loop runs zero times and the skb DMA mapping in
buf[1] is never unmapped. buf[1].skip_unmap is set unconditionally, so the
generic DMA-ring cleanup skips it as well.
Each AddBA req therefore leaks one TX DMA mapping, roughly one per
(re)association. With WED enabled these mappings are bounced through the
WED swiotlb pool, so under continuous client reconnect churn the pool is
exhausted after ~1-2 days, after which DMA mapping fails for WED, the WiFi
MCU and other on-SoC
Scoring
| EPSS | 0.21% probability of exploitation · percentile 9.7% · 2026-10-05T12:00:23Z |
| Last modified | 2026-09-11 |