CVE-2016-7914

What it actually does

Missing leaf-slot check in assoc_array_insert_into_terminal_node allows invalid pointer dereference or out-of-bounds kernel read when an associative-array insert occurs on a non-leaf slot.

Why it matters to the business

Local users on unpatched Linux systems can leak kernel memory contents or trigger kernel crashes, impacting confidentiality and system availability on legacy or embedded deployments.

How an attack unfolds

A local attacker compiles or runs an application (such as the keyutils test suite) that performs associative-array operations; the crafted insert reaches the vulnerable terminal-node path and dereferences a non-leaf pointer, either reading kernel memory or causing an oops.

How to fix it

Upgrade the Linux kernel to a version containing commit 8d4a2ec1e0b41b0cf9a0c5cd4511da7f8e4f3de2 (equivalent to 4.5.3 or later distributions). Reboot after installation.

How to confirm the fix worked

Run 'uname -r' and confirm kernel version >= 4.5.3; alternatively verify the presence of the cited commit in the running kernel source or package changelog.

Typical attack path

1. Obtain local shell or process execution on target Linux host
2. Invoke or craft an application that exercises associative-array insert operations
3. Trigger insertion into a terminal node containing a non-leaf slot
4. Observe kernel memory disclosure or kernel panic/DoS

How to detect it

Examine audit logs and process execution records for unusual invocations of keyutils or custom associative-array test programs; correlate with kernel oops or panic entries referencing assoc_array.

What your security team should do

• Prioritize kernel upgrades on any remaining systems older than 4.5.3
• Enforce least-privilege local accounts to reduce attack surface
• Review and remove unnecessary key-management or associative-array test binaries