CVE-2026-16529

A signed integer overflow in the PCP __pmGetPDU() function can be exploited via crafted network packets during PDU processing or SASL negotiation. This permanently blinds the affected daemon, resulting in a total denial of service (DoS) for subsequent packet reads.

This is an Important denial of service vulnerability in PCP due to a signed integer overflow. An unauthenticated remote attacker could exhaust resources by sending a specially crafted request to the pmlogger or pmcd services, leading to a permanent denial of service for the affected daemon. While both services are typically bound to the loopback interface by default, remote exploitation is possible if the default binding configuration is altered or if PMLOGGER_LOCAL is unset for pmlogger.

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, ensure that Performance Co-Pilot (PCP) services, specifically pmlogger and pmcd, are not exposed to untrusted networks. By default, these services are configured to listen only on the loopback interface, which prevents remote exploitation. If these default network bindings have been altered, revert them to restrict access to localhost. For pmlogger, ensure the PMLOGGER_LOCAL environment variable is set. If remote access to PCP services is not required, consider implementing firewall rules to block external connections to TCP ports 4330 (pmlogger) and 44321 (pmcd). Changes to network configurations or environment variables may require restarting the affected PCP services for the mitigation to take effect.