Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-07-24T00:00:00 kernel: wifi: iwlwifi: mld: validate sta_mask before ffs() in BA session handlers 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CWE-823

In the Linux kernel, the following vulnerability has been resolved: wifi: iwlwifi: mld: validate sta_mask before ffs() in BA session handlers Three BA session handlers use ffs(ba_data->sta_mask) - 1 to derive a station ID without checking that sta_mask is non-zero. When sta_mask is zero, ffs() returns 0 and the subtraction wraps to 0xFFFFFFFF, causing an out-of-bounds access on fw_id_to_link_sta[]. Add WARN_ON_ONCE(!ba_data->sta_mask) guards before each ffs() call, consistent with the existing check in iwl_mld_ampdu_rx_start().

A flaw was found in the Linux kernel's iwlwifi (Intel Wireless WiFi) driver. This vulnerability allows an attacker to cause an out-of-bounds memory access in the WiFi Block Acknowledgement (BA) session handlers. This occurs when the `sta_mask` value is zero, leading to an incorrect station ID calculation and potential system instability or denial of service.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-64255 https://nvd.nist.gov/vuln/detail/CVE-2026-64255 https://lore.kernel.org/linux-cve-announce/2026072420-CVE-2026-64255-f09c@gregkh/T