CVE-2021-47030

What it actually does

A memory leak occurs in the mt7615_coredump_work routine because allocated memory is not freed on certain code paths, similar to a prior fix in mt7921_coredump_work.

Why it matters to the business

Repeated triggering of the affected wireless driver on Debian 11 systems can gradually exhaust kernel memory, causing performance degradation, instability, or crashes that disrupt operations until reboot or patch.

How an attack unfolds

An attacker with local access triggers wireless events or error conditions that invoke mt7615_coredump_work repeatedly; each invocation leaks memory without release, leading to eventual resource exhaustion on unpatched kernels.

How to fix it

Upgrade the Linux kernel package to version 5.10.221-1 or later on all Debian 11 systems; apply the update via standard package management and reboot affected hosts.

How to confirm the fix worked

Confirm the running kernel version is 5.10.221-1 or newer using uname or package queries; monitor memory usage during wireless error scenarios to verify leak resolution.

Typical attack path

1. Confirm presence of mt7615 hardware and vulnerable kernel version on target system
2. Trigger conditions that cause repeated invocation of mt7615_coredump_work
3. Observe progressive kernel memory depletion over multiple invocations

How to detect it

Review kernel logs and memory usage metrics for repeated mt7615_coredump_work activity correlated with unexplained memory growth; no specific post-exploitation artifacts are known.

What your security team should do

• Prioritize kernel updates on all Debian 11 systems with mt7615 hardware within standard maintenance windows
• Monitor kernel memory statistics and wireless driver logs for anomalous growth patterns
• Restrict local access where feasible until patches are deployed