CVE-2024-42130

What it actually does

The flaw permits a write operation where supplied data length is shorter than the declared count value, bypassing validation before nci_rf_intf_activated_ntf_packet processes the buffer and allowing under-read conditions in the NFC NCI subsystem.

Why it matters to the business

Linux-based systems handling NFC communications face elevated crash or instability risk in kernel space, potentially disrupting device functionality and requiring urgent patching across fleets of servers, embedded devices, and Android kernels that incorporate the affected code.

How an attack unfolds

An attacker invokes the write syscall on the NCI device with a 3-byte payload but a 15-byte count, passing the malformed request into the packet handler; threat actors in 2024 zero-day campaigns and Linux kernel exploitation efforts could leverage this to induce inconsistent state or trigger downstream faults without authentication.

How to fix it

Apply the upstream fix in commit f07bcd8bba803c9e6ad2048543185d6c56587a2f or later stable releases that add the data-length versus count consistency check; rebuild and deploy the patched kernel across all affected distributions and embedded images.

How to confirm the fix worked

Confirm the presence of the length-versus-count comparison in nci_rf_intf_activated_ntf_packet after patching; re-run syzbot-style fuzzing or targeted write tests to verify the inconsistency is now rejected.

Typical attack path

1. Open the NCI character device
2. Construct a write call supplying fewer bytes than the count argument
3. Invoke nci_rf_intf_activated_ntf_packet with the truncated buffer
4. Trigger kernel fault or undefined behavior from length mismatch

How to detect it

Review kernel logs for NCI packet handling warnings or faults around write operations; search audit trails for unusual write calls to /dev/nci* character devices by unprivileged processes.

What your security team should do

• Prioritize kernel upgrades to the fixed commit on all production and edge Linux systems within the CISA-style remediation window
• Monitor vendor advisories for backported patches in LTS kernels and Android common kernels
• Restrict unprivileged access to NCI device nodes via udev rules or SELinux policies until patched