CVE-2024-46831

What it actually does

A use-after-free vulnerability in the Linux kernel vcap kunit test code allows access to freed memory after vcap_del_rule is called.

Why it matters to the business

Potential kernel instability or crashes during testing of network virtual capture features on Linux systems, increasing risk for development environments and downstream distributions.

How an attack unfolds

An attacker triggers execution of the affected kunit test path in the vcap module, causing the test to reference memory that has already been freed by vcap_del_rule.

How to fix it

Update the Linux kernel to the fixed commit b0804c286ccfcf5f5c004d5bf8a54c0508b5e86b or later stable releases containing the removal of the use-after-free access and reliance on the vcap_del_rule return code.

How to confirm the fix worked

Inspect kernel source or running kernel version for the presence of the fix commit; confirm vcap kunit tests pass without use-after-free warnings and that rule deletion properly checks return codes.

Typical attack path

1. Identify systems running vulnerable Linux kernel versions with vcap kunit tests enabled
2. Trigger the specific kunit test execution for the microchip vcap module
3. Force vcap_del_rule call to free the rule object
4. Access the dangling pointer to trigger use-after-free

How to detect it

Review kernel logs for use-after-free warnings or oops messages referencing vcap_del_rule or kunit test execution in the microchip vcap module.

What your security team should do

• Prioritize kernel updates on build, test, and CI systems using affected vcap modules
• Disable or isolate kunit tests in production kernel configurations
• Monitor for related kernel memory safety issues in future releases