CVE-2024-47674

What it actually does

In Linux kernel mm code, error paths for PFN mappings can free physical backing store before tearing down page table entries, leaving stale dangling PTEs that reference freed memory and enabling use-after-free conditions.

Why it matters to the business

Linux systems may experience crashes, memory corruption, or local privilege escalation, impacting server stability, container hosts, and embedded devices across the ecosystem; the issue has been public for an extended period with low but persistent exploit probability.

How an attack unfolds

An attacker triggers a failing mmap operation on a PFN mapping, races the error cleanup to access dangling PTE entries that point to freed pages, and uses the resulting use-after-free primitive to corrupt kernel structures or escalate privileges. Listed threat actor campaigns and related Linux kernel privilege-escalation CVEs illustrate how such memory-management flaws are leveraged in espionage and financially motivated operations.

How to fix it

Upgrade the Linux kernel to the fixed commit 3213fdcab961026203dd587a4533600c70b3336b or later stable releases containing the patch; apply distribution-specific updates that backport the change. Cosmos SDK users should move to version 0.47.10 or newer.

How to confirm the fix worked

Confirm the running kernel contains commit 3213fdcab961026203dd587a4533600c70b3336b or a backport; review kernel build logs or git history for the mm/page_table.c or equivalent change; test mmap error paths with fault-injection tools to verify cleanup order.

Typical attack path

1. Identify or trigger an mmap call that will fail after partial PFN mapping setup
2. Force the error path while the physical backing store is released before PTE teardown
3. Access the stale PTE to read or write freed memory
4. Corrupt kernel data structures to gain elevated privileges or execute arbitrary code

How to detect it

Search kernel logs and audit trails for unexpected page-fault or oops messages involving PFN mappings or mmap failures; correlate with process execution of unprivileged code that performs many mmap/munmap operations; review any post-exploitation artifacts from the referenced threat actor campaigns.

What your security team should do

• Prioritize kernel updates on all Linux hosts within the next patch cycle given the use-after-free class and public availability
• Monitor EPSS trend and any new exploitation reports from listed threat actors
• Enable kernel hardening features such as KASAN or page-table isolation where performance permits
• Review custom drivers or modules that perform PFN mappings for similar error-handling patterns