CVE-2026-46174

What it actually does

This is a Linux kernel flaw affecting AMD Zen 2 systems where shared CPU resources in the operation cache may not be properly isolated. Under specific local execution conditions, instruction corruption can occur across isolation boundaries, potentially letting a low-privileged local user influence execution in a way that breaks confidentiality, integrity, or availability guarantees. Because the vulnerability is local and requires an existing ability to run code on the system, it is primarily a privilege-escalation and isolation-bypass risk rather than a remotely exploitable network flaw.

Why it matters to the business

If exploited, an attacker who already has local user-level access to an affected Linux system could potentially escalate privileges, tamper with workloads, access sensitive data, or destabilize the host. This is most concerning for shared compute, multi-user Linux servers, CI/CD runners, developer workstations, virtualization hosts, container platforms, and high-density environments using AMD Zen 2 CPUs. The vulnerability is not currently listed in CISA KEV, has low EPSS, and has no known mature public exploit, but the high CVSS score means organizations should still prioritize kernel updates where affected hardware is present.

How an attack unfolds

An attacker would first need to obtain the ability to execute code locally on an affected Linux system, such as through a compromised user account, malicious workload, container escape chain, build runner abuse, or post-exploitation foothold. The attacker would then run code designed to exercise the affected AMD Zen 2 operation-cache behavior and attempt to trigger improper sharing of CPU-internal resources. If successful, instruction corruption could occur in a way that undermines normal execution isolation, potentially enabling privilege escalation, sensitive data exposure, process or kernel memory corruption, or denial of service. Because this issue is tied to low-level CPU and kernel behavior, exploitation is expected to be hardware- and kernel-version-dependent and may be difficult to confirm from ordinary application logs.

How to fix it

Apply the Linux kernel update from the operating system or distribution vendor that includes the upstream fix for the AMD Zen 2 operation-cache isolation issue. No exact fixed package versions were provided in the input, so remediation should be based on vendor advisories for the deployed distribution and kernel stream. Prioritize systems with AMD Zen 2 processors, especially shared-user servers, virtualization hosts, container hosts, build infrastructure, and internet-facing systems where local compromise would have high impact. If immediate patching is not possible, reduce exposure by limiting untrusted local code execution, tightening shell and SSH access, restricting container privileges, disabling unnecessary user accounts, enforcing least privilege, and isolating untrusted workloads from sensitive hosts. Consider applying relevant CPU microcode or firmware updates if recommended by the hardware or operating system vendor, but treat the kernel fix as the primary remediation path unless vendor guidance states otherwise.

How to confirm the fix worked

Confirm whether systems are exposed by checking for AMD Zen 2 CPUs and verifying the installed kernel package against the operating system vendor advisory that contains the fix. On Linux, defenders can review CPU model information with standard inventory tools or /proc/cpuinfo and compare the running kernel version from uname -r against patched distribution versions. After remediation, reboot into the updated kernel and confirm the active kernel is the fixed version, not merely installed alongside an older vulnerable kernel. Validate that kernel live-patching, if used, explicitly covers this issue. For fleet validation, query endpoint management, vulnerability scanners, configuration management, and package inventories for AMD Zen 2 hosts still running vulnerable kernel builds.

Typical attack path

1. Gain local code execution on an affected Linux system, either through stolen credentials, an exposed service compromise, malicious job execution, or another vulnerability.
2. Determine that the host is running on affected AMD Zen 2 hardware and a vulnerable Linux kernel build.
3. Run a local exploit or proof-of-concept designed to manipulate operation-cache behavior and trigger instruction corruption.
4. Use the resulting isolation failure to attempt privilege escalation, tampering with privileged execution, data access, or system disruption.
5. Establish persistence, access sensitive files or credentials, pivot to other systems, or disrupt workloads if higher privileges are obtained.

How to detect it

There are no reliable network indicators for this vulnerability because exploitation requires local code execution and abuses low-level CPU/kernel behavior. To assess possible prior exploitation, review endpoint and system telemetry for signs of local privilege escalation or unstable kernel behavior around the time suspicious users, jobs, containers, or processes executed. Useful sources include auditd logs, authentication logs, sudo logs, shell history where available, EDR process telemetry, container runtime logs, kernel logs, crash dumps, systemd journal, package integrity results, and file integrity monitoring. Look for unexpected transitions from low-privileged users to root, new or modified setuid/setgid binaries, suspicious writes to privileged paths, unexpected kernel oops/panic messages, unexplained process crashes, abnormal compiler or exploit-like workloads in temporary directories, and unauthorized persistence mechanisms. Because EPSS is low, the CVE is not in KEV, and exploit maturity is listed as none, broad opportunistic exploitation is not currently indicated by the provided data; however, targeted local exploitation may leave only indirect artifacts.

• /var/log/auth.log
• /var/log/secure
• /var/log/audit/audit.log
• /var/log/kern.log
• /var/log/messages
• /var/crash/
• /var/lib/systemd/coredump/
• kernel: oops
• kernel: BUG:
• kernel: general protection fault
• kernel: segfault
• kernel: panic
• COMMAND=/bin/bash
• COMMAND=/bin/sh
• /tmp/
• /var/tmp/
• /dev/shm/
• chmod u+s
• chmod 4755
• setuid
• setgid

What your security team should do

• Inventory Linux systems running on AMD Zen 2 hardware and identify those using vulnerable kernel versions.
• Prioritize patching shared compute, container hosts, virtualization hosts, CI/CD runners, developer-accessible systems, and other environments where untrusted local code can run.
• Apply vendor-provided kernel updates and reboot systems into the fixed kernel; verify the running kernel after reboot.
• Review whether CPU microcode or firmware updates are recommended by the hardware or Linux distribution vendor and apply them through normal change control.
• Restrict local interactive access and untrusted workload execution until patching is complete.
• Increase monitoring for local privilege escalation indicators, unexpected root shells, suspicious setuid changes, kernel crashes, and anomalous process behavior on affected systems.
• Treat exploitation as difficult to prove directly from logs; if compromise is suspected, perform host-based forensic review rather than relying only on application telemetry.
• Track vendor advisories because exact fixed versions may differ across Linux distributions and kernel branches.