CVE-2023-54260

What it actually does

Resource leak of SMB Direct connection information when memory registration allocation fails during connection setup, causing smbd_destroy to return early without cleanup.

Why it matters to the business

Over time, repeated allocation failures in SMB Direct paths can exhaust kernel resources on Linux systems performing CIFS file sharing, leading to degraded performance or instability in networked storage operations.

How an attack unfolds

An attacker with network access to trigger SMB Direct negotiation and force memory registration failures can cause gradual resource leakage in the CIFS client without explicit exploitation steps beyond normal connection attempts.

How to fix it

Update the Linux kernel to a version containing commit d303e25887127364a6765eaf7ac68aa2bac518a9 or later stable releases; apply vendor-supplied kernel updates for affected distributions.

How to confirm the fix worked

Verify kernel source contains the fix commit or confirm package version matches the listed fixed versions; test SMB Direct connection paths under memory pressure to ensure no leaks occur.

Typical attack path

1. Establish SMB Direct connection to target Linux CIFS client
2. Induce memory registration allocation failure during connection setup
3. Trigger early return in smbd_destroy leaving connection info leaked
4. Repeat to accumulate resource exhaustion

How to detect it

Review kernel logs for repeated SMB Direct allocation failures or connection setup errors; inspect memory usage patterns in CIFS/SMB modules during high-connection scenarios.

What your security team should do

• Prioritize kernel updates on systems using CIFS with SMB Direct enabled
• Monitor for resource exhaustion symptoms in CIFS workloads
• Review and apply stable kernel patches within standard maintenance windows given low EPSS and no KEV status