CVE-2023-53751

What it actually does

Use-after-free condition in TCP_Server_Info::hostname when the field is accessed outside the reconnect path after being updated or freed during reconnection handling in the CIFS module.

Why it matters to the business

Kernel memory corruption risk in systems performing CIFS/SMB file sharing can lead to crashes, degraded storage connectivity, or potential local privilege escalation; low public exploitability reduces immediate widespread impact but still requires prompt patching on affected kernels and dependent components.

How an attack unfolds

An attacker with local access or the ability to influence CIFS reconnection events (such as network interruptions) races concurrent accesses to the hostname field while it is being updated or freed, triggering the use-after-free; no named threat actors or ransomware campaigns are associated.

How to fix it

Apply kernel updates containing commit 64d62ac6d6514cba1305bd08e271ec1843bdd612 or later; for the aws-load-balancer-controller component update to version 2.8.2 or newer; verify the fix is present in running kernels via uname and module inspection.

How to confirm the fix worked

Confirm the patched commit or version string appears in the running kernel source or binary; monitor for absence of prior unstable hostname access patterns in kernel logs after upgrade.

Typical attack path

1. Establish or maintain a CIFS mount that triggers periodic or forced reconnects
2. Induce timing where hostname is freed or replaced during reconnect
3. Perform concurrent read or dereference of the hostname pointer from another code path
4. Trigger kernel memory corruption leading to crash or controlled execution

How to detect it

Review kernel logs for use-after-free warnings or slab corruption messages referencing cifs or TCP_Server_Info; examine audit logs around CIFS mount and reconnect events for anomalous process activity coinciding with crashes.

What your security team should do

• Prioritize patching kernels on all systems using CIFS mounts within standard change windows given the 325-day publication age
• Inventory workloads dependent on the listed affected packages and schedule upgrades to the stated fixed versions
• Enable kernel hardening features such as KASAN or hardened allocators where feasible to reduce UAF impact