CVE-2026-16527

An unauthenticated remote attacker can bypass access controls by sending crafted requests to the PCP pmproxy /store endpoint. This allows the attacker to overwrite any PMDA metric, leading to arbitrary code execution and system takeover.

This is an Important flaw in Performance Co-Pilot (PCP) pmproxy that allows an unauthenticated remote attacker to bypass pmcd access controls. By sending crafted requests to the /store endpoint, an attacker can write to any Performance Metrics Domain Agent (PMDA) metric, potentially leading to arbitrary code execution if pmproxy is running and reachable on its default port.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, restrict network access to the pmproxy service (port 44322/TCP) to trusted hosts only using firewall rules. If pmproxy functionality is not required, disable the service. Disabling the service will prevent remote access to performance metrics via pmproxy. To disable the service, run: sudo systemctl stop pmproxy and sudo systemctl disable pmproxy. If firewalling, ensure to reload the firewall rules after making changes.