wifi: mac80211: bounds-check link_id in ieee80211_ml_epcs

Summary

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").

Timeline

1. Jul 19, 2026, 3:39 PM UTCCVE published
2. Oct 16, 2026, 3:35 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Oct 19, 2026, 8:28 PM UTCRecord last updated

Affected versions

• Linux Linux

  From de86c5f60839dc0d771711a848b4f55ad3f90844 · fixed in 2d8379834800c30602f24c71ab7c40f5fe84d200; From de86c5f60839dc0d771711a848b4f55ad3f90844 · fixed in 863f1f02a3bd70dbd857b8ac4070292fde8cb4e2; From de86c5f60839dc0d771711a848b4f55ad3f90844 · fixed in f718506edd2d9c6a308ded9d13c632bf7b7d5a2c

• Linux Linux

  6.15

• KernelLinux

  From 6.15.0 · fixed in 6.18.34; From 6.19.0 · fixed in 7.0.11

References 3