CVE-2024-40929

What it actually does

Out-of-bounds memory access in the iwlwifi mvm driver when n_ssids is zero but the ssids pointer remains valid, allowing invalid pointer dereference.

Why it matters to the business

Kernel instability, potential crashes, or code execution on Linux systems using Intel wifi hardware during wireless scanning operations, increasing downtime and exposure risk across server and endpoint fleets.

How an attack unfolds

An attacker with local or adjacent network access triggers a cfg80211 scan request that sets n_ssids to zero while supplying a valid ssids pointer; the driver then dereferences the pointer without a bounds check, leading to memory corruption that can be chained for privilege escalation or denial of service.

How to fix it

Apply the upstream fix by updating the Linux kernel to commit 3c4771091ea8016c8601399078916f722dd8833b or later stable releases containing the n_ssids guard; rebuild and deploy the patched kernel image across all affected systems.

How to confirm the fix worked

Confirm the commit 3c4771091ea8016c8601399078916f722dd8833b is present in the running kernel source; test wireless scan operations under n_ssids=0 conditions to ensure no crash or corruption occurs.

Typical attack path

1. Obtain local or Wi-Fi adjacent access to a vulnerable Linux system
2. Craft or trigger a scan request via cfg80211 with n_ssids=0 and a valid ssids pointer
3. iwlwifi mvm code path accesses ssids without prior n_ssids validation
4. Out-of-bounds read/write occurs, enabling memory corruption
5. Chain corruption to achieve code execution or system crash

How to detect it

Review kernel logs for oops or panic messages referencing iwlwifi mvm and ssids access; inspect wireless driver stack traces for n_ssids-related faults; correlate with threat actor campaigns targeting Linux kernel memory issues.

What your security team should do

• Prioritize kernel upgrades on all systems using iwlwifi within the next maintenance window
• Monitor EPSS and threat actor reports for any rise in exploitation activity
• Harden wireless configurations to reduce unnecessary scan exposure where feasible
• Include the patched commit in automated kernel build and deployment pipelines