CVE-2022-0264

What it actually does

The eBPF verifier incorrectly returns internal kernel memory addresses to userspace, enabling leakage of sensitive kernel data structures that can bypass address space layout randomization and other mitigations.

Why it matters to the business

Organizations running vulnerable Linux kernels face increased risk of kernel memory disclosure by local users with eBPF insertion rights, potentially aiding further attacks against kernel protections and requiring urgent patching of widely deployed systems.

How an attack unfolds

An attacker with local access and the ability to load eBPF programs crafts a malicious verifier input that triggers the flaw, causing the kernel to disclose internal memory locations back to userspace; this information is then used to defeat mitigations and facilitate further privilege escalation attempts, consistent with observed Linux kernel exploitation patterns by threat actors targeting similar issues.

How to fix it

Upgrade the Linux kernel to a version containing commit df0cc57e057f18e44dac8e6c18aba47ab53202f9 or later; rebuild and reboot all affected systems, and restrict untrusted local users from loading eBPF programs via kernel configuration options such as CONFIG_BPF_SYSCALL=n where feasible.

How to confirm the fix worked

Confirm the running kernel version is at or above the fixed commit; attempt to load test eBPF programs that previously triggered the verifier leak and verify no internal addresses are returned; monitor kernel build logs for the presence of the patching commit.

Typical attack path

1. Obtain local shell access on a vulnerable Linux system
2. Acquire permissions required to insert eBPF bytecode (typically CAP_SYS_ADMIN or equivalent)
3. Load a crafted eBPF program that exercises the verifier flaw
4. Read leaked kernel memory addresses from userspace
5. Use disclosed addresses to bypass exploit mitigations and escalate privileges

How to detect it

Review audit logs for unusual eBPF program loads by non-root or untrusted users; inspect kernel logs for verifier-related warnings around the time of suspicious activity; correlate with process execution of bpftool or similar utilities.

What your security team should do

• Immediately identify and prioritize patching of all systems running kernels older than v5.16-rc6
• Restrict eBPF program loading to trusted processes only via LSM or capability controls
• Enable kernel address space layout randomization and other available mitigations
• Monitor for new kernel releases and apply updates within standard change windows