CVE-2022-48641

What it actually does

Incomplete fix in netfilter ebtables causes a memory leak on malformed blob input instead of a crash, due to missing assignment restoration in conditional logic.

Why it matters to the business

Over time, repeated processing of malformed network filtering data on Linux systems can exhaust memory resources, degrading performance or causing denial of service in environments relying on ebtables for packet inspection.

How an attack unfolds

An attacker supplies a malformed blob to the ebtables subsystem in the Linux kernel; the flawed error-handling path leaks allocated memory without proper cleanup or return-value assignment, gradually consuming kernel memory without immediate crash.

How to fix it

Update the Linux kernel to the fixed commit 754e8b74281dd54a324698803483f47cf3355ae1 or later stable versions containing the restored return-value assignment and leak prevention in ebtables.

How to confirm the fix worked

Verify kernel source or running version includes commit 754e8b74281dd54a324698803483f47cf3355ae1; test ebtables with malformed blobs and confirm no memory growth via slabinfo or kmemleak.

Typical attack path

1. Identify systems exposing ebtables interfaces or processing untrusted network configuration blobs.
2. Craft and deliver malformed blob data triggering the incomplete error path.
3. Repeat delivery to accumulate leaked memory allocations over time.
4. Monitor for resource exhaustion symptoms without triggering crashes.

How to detect it

Review kernel memory statistics and logs for unusual slab allocations tied to ebtables; correlate with network configuration changes or blob processing events in systems running vulnerable kernels.

What your security team should do

• Prioritize kernel upgrades to the listed fixed commit across all affected Linux distributions.
• Monitor memory usage in ebtables-enabled environments until patches are applied.
• Review ebtables usage and restrict untrusted blob processing where feasible.