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CVE-2026-64175

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mld: stop TX during firmware restart When iwlwifi firmware crashes (e.g., NMI_INTERRUPT_UNKNOWN on Intel BE201/Wi-Fi 7), iwl_mld_nic_error() sets mld->fw_status.in_hw_restart to true. However, iwl_mld_tx_from_txq() does not check this flag before dequeuing frames from mac80211 and pushing them to the transport layer. Since the firmware is dead, iwl_trans_tx() returns -EIO for each frame, which then gets freed immediately. Under high-throughput conditions (e.g., Tailscale UDP traffic or active SSH sessions), this creates a tight dequeue-send-fail-free loop that wastes CPU cycles and generates rapid skb allocation churn, leading to memory pressure from slab fragmentation. The RX path already has this guard (iwl_mld_rx_mpdu checks in_hw_restart at rx.c:1906), and so does the TXQ allocation worker (iwl_mld_add_txqs_wk at tx.c:156). Add the same guard to iwl_mld_tx_from_txq() to stop all TX during firmware restart. Frames left in mac80211's TXQs are naturally drained after restart completes, when queue reallocation triggers iwl_mld_tx_from_txq() via iwl_mld_add_txq_list(), or when new upper-layer traffic invokes wake_tx_queue. Tested on ASUS Zenbook 14 UX3405CA with Intel BE201 (Wi-Fi 7) on kernel 6.19.5 where the firmware crashes approximately every 10-15 minutes under Tailscale traffic.

Severity
HIGH
CVSS score
7.5 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-07-19 16:17:59.750000
Last modified
2026-10-19 21:17:26.043000
View original CVE JSON 
{
  "id": "CVE-2026-64175",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-07-19T16:17:59.750",
  "lastModified": "2026-10-19T21:17:26.043",
  "vulnStatus": "Modified",
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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: iwlwifi: mld: stop TX during firmware restart\n\nWhen iwlwifi firmware crashes (e.g., NMI_INTERRUPT_UNKNOWN on Intel\nBE201/Wi-Fi 7), iwl_mld_nic_error() sets mld->fw_status.in_hw_restart\nto true. However, iwl_mld_tx_from_txq() does not check this flag before\ndequeuing frames from mac80211 and pushing them to the transport layer.\n\nSince the firmware is dead, iwl_trans_tx() returns -EIO for each frame,\nwhich then gets freed immediately. Under high-throughput conditions\n(e.g., Tailscale UDP traffic or active SSH sessions), this creates a\ntight dequeue-send-fail-free loop that wastes CPU cycles and generates\nrapid skb allocation churn, leading to memory pressure from slab\nfragmentation.\n\nThe RX path already has this guard (iwl_mld_rx_mpdu checks\nin_hw_restart at rx.c:1906), and so does the TXQ allocation worker\n(iwl_mld_add_txqs_wk at tx.c:156). Add the same guard to\niwl_mld_tx_from_txq() to stop all TX during firmware restart.\n\nFrames left in mac80211's TXQs are naturally drained after restart\ncompletes, when queue reallocation triggers iwl_mld_tx_from_txq()\nvia iwl_mld_add_txq_list(), or when new upper-layer traffic invokes\nwake_tx_queue.\n\nTested on ASUS Zenbook 14 UX3405CA with Intel BE201 (Wi-Fi 7) on\nkernel 6.19.5 where the firmware crashes approximately every 10-15\nminutes under Tailscale traffic."
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          "baseScore": 7.5,
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