CVE-2023-52531

What it actually does

Incorrect pointer arithmetic due to an erroneous (u8*) cast when initializing the bitrates flex-array member of iwl_nvm_data causes the pointer to land inside the channels array instead of the adjacent ieee80211_rate allocation, resulting in out-of-bounds writes during subsequent wifi NVM setup.

Why it matters to the business

Systems running affected Linux kernels with Intel wireless hardware face risk of kernel memory corruption that can produce crashes, denial of service, or local privilege escalation; the issue affects a broad set of stable kernel trees and requires prompt patching to avoid operational disruption on servers, workstations, and embedded devices.

How an attack unfolds

An attacker with the ability to trigger the iwlwifi mvm NVM initialization path (for example by bringing up the wireless interface or inserting the module) causes the miscalculated bitrates pointer to be dereferenced and written, corrupting adjacent kernel structures and potentially leading to arbitrary code execution or a crash.

How to fix it

Upgrade the Linux kernel to the commit 7c8faa31080342aec4903c9acb20caf82fcca1ef or later stable releases that contain the corrected pointer arithmetic; rebuild and reboot all affected systems; where immediate patching is impossible, restrict wireless interface usage or unload the iwlwifi module if operationally feasible.

How to confirm the fix worked

Confirm the running kernel contains commit 7c8faa31080342aec4903c9acb20caf82fcca1ef by inspecting /proc/version or the kernel build log; attempt to initialize the wireless interface and monitor for memory corruption warnings or crashes in dmesg; review the iwlwifi mvm source for removal of the (u8*) cast on the channels pointer arithmetic.

Typical attack path

1. Obtain local or physical access sufficient to load or interact with the iwlwifi driver
2. Trigger wireless interface bring-up or module insertion to execute the faulty NVM allocation path
3. Trigger the bands[0].bitrates assignment that performs the erroneous pointer arithmetic
4. Perform subsequent operations that dereference the corrupted pointer to achieve memory corruption or control-flow hijack

How to detect it

Search kernel logs and dmesg for iwlwifi or mvm initialization messages around the time of any crash or unexpected reboot; inspect for signs of slab or page allocator corruption following wireless interface activation; review audit logs for module loads of iwlwifi on systems that later exhibited instability.

What your security team should do

• Prioritize kernel upgrades on all Internet-facing or multi-user Linux systems containing Intel wireless hardware
• Monitor vendor and distribution advisories for backported fixes in supported LTS kernels
• Temporarily disable or blacklist the iwlwifi module on systems where wireless is not required until patched
• Include the corrected commit identifier in automated kernel build and deployment pipelines