CVE-2023-32269

What it actually does

Use-after-free in net/netrom/af_netrom.c triggered when accept() is called on a successfully connected AF_NETROM socket, allowing a local user with CAP_NET_ADMIN or netrom routing enabled to access freed kernel memory.

Why it matters to the business

Local attackers with administrative network privileges can crash systems or execute arbitrary code in the kernel, resulting in loss of control, data exposure, and downtime on affected Linux hosts.

How an attack unfolds

An attacker with CAP_NET_ADMIN or netrom routing configured creates and connects an AF_NETROM socket, then invokes accept() on the connected socket to trigger the use-after-free condition and manipulate freed memory for privilege escalation or denial of service.

How to fix it

Upgrade the Linux kernel to version 6.1.11 or later containing commit d60c95efffe84428e3611431bf688f50bfc13f4e; disable netrom routing if unused and restrict CAP_NET_ADMIN to trusted processes.

How to confirm the fix worked

Verify kernel version is at least 6.1.11, confirm presence of commit d60c95efffe84428e3611431bf688f50bfc13f4e in the source tree, and test that accept() on connected AF_NETROM sockets no longer triggers use-after-free.

Typical attack path

1. Obtain CAP_NET_ADMIN capability or enable netrom routing
2. Create and successfully connect an AF_NETROM socket
3. Call accept() on the connected socket to trigger the race condition
4. Exploit the freed memory object for code execution or crash

How to detect it

Search kernel logs and audit records for netrom socket operations, unexpected accept() calls on AF_NETROM, and oops/panic messages referencing af_netrom.c; correlate with processes holding CAP_NET_ADMIN.

• netrom.*accept
• af_netrom.c
• use-after-free.*netrom

What your security team should do

• Apply kernel update containing the referenced fix commit immediately on all systems
• Audit and minimize use of netrom protocol and CAP_NET_ADMIN grants
• Monitor kernel logs for netrom-related oops or warnings as a compensating control