CVE-2025-38461

What it actually does

Race condition in vsock_assign_transport allows transport pointer to become stale during module unload, leading to use-after-free and kernel page fault on subsequent connect operations.

Why it matters to the business

Kernel crashes or potential privilege escalation in Linux systems using vsock (virtual sockets), disrupting containerized workloads, virtual machines, and cloud instances with possible unauthorized code execution.

How an attack unfolds

An attacker triggers concurrent vsock_connect and module unload operations; the stale transport pointer dereference during assignment or vsock_use_local_transport leads to controlled memory corruption or crash, which advanced spyware and privilege escalation campaigns chain with other kernel bugs for container escape.

How to fix it

Update Linux kernel to commit 8667e8d0eb46bc54fdae30ba2f4786407d3d88eb or later stable release containing the vsock transport locking fix; rebuild and deploy affected distributions.

How to confirm the fix worked

Confirm kernel version includes commit 8667e8d0eb46bc54fdae30ba2f4786407d3d88eb; run vsock stress tests under module unload conditions and verify absence of page faults or KASAN reports.

Typical attack path

1. Identify vsock-enabled environment (containers, VMs)
2. Race vsock_connect syscall against transport module unload
3. Trigger stale pointer dereference in vsock_assign_transport
4. Exploit resulting memory corruption for privilege escalation
5. Pivot to container escape or kernel-level persistence

How to detect it

Search kernel logs for 'vsock_assign_transport' oops, page faults at fffffbfff8056000, and KASAN reports during connect syscalls; correlate with module unload events in dmesg and audit logs.

• RIP: 0010:vsock_assign_transport+0x366/0x600
• BUG: unable to handle page fault for address: fffffbfff8056000
• Call Trace: vsock_connect+0x59c/0xc40

What your security team should do

• Prioritize kernel upgrade on all systems exposing vsock interfaces within 30 days
• Monitor for kernel oops involving vsock_assign_transport in production logs
• Restrict vsock usage to trusted workloads until patched
• Audit container runtimes and hypervisors for vsock dependencies