CVE-2026-16524
Description
A command injection flaw in PCP's linux_sockets PMDA allows malicious shell metacharacters via the network.persocket.filter metric. This failed validation lets attackers execute arbitrary commands as the PMDA user when metrics refresh.
Statement
This flaw is rated as Important because it allows a local attacker to achieve arbitrary command execution as the PMDA process user within the Performance Co-Pilot (PCP) environment. Exploitation requires the linux_sockets PMDA to be loaded and the ss utility to be present, which are common configurations. The vulnerability stems from an inverted validation logic in the sockets_check_filter() function, enabling the injection of malicious shell metacharacters into a filter value that is later executed.
Mitigation
To prevent exploitation, restrict access to the `pmstore` utility by configuring the `[access]` section in `/etc/pcp/pmcd/pmcd.conf`. If the `linux_sockets` PMDA is not essential, it can be unloaded or disabled to remove the attack vector. After modifying `pmcd.conf`, the `pmcd` service must be restarted for changes to take effect.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.8 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability,Non-Repudiation
Technical Impact: Execute Unauthorized Code or Commands; DoS: Crash, Exit, or Restart; Read Files or Directories; Modify Files or Directories; Read Application Data; Modify Application Data; Hide Activities
Attackers could execute unauthorized operating system commands, which could then be used to disable the product, or read and modify data for which the attacker does not have permissions to access directly. Since the targeted application is directly executing the commands instead of the attacker, any malicious activities may appear to come from the application or the application's owner.
Acknowledgements
Red Hat would like to thank Francisco Alisson Bezerra (TIM Security Red Team Research, TIM S.p.A), Lucas Gabriel Alves (TIM Security Red Team Research, TIM S.p.A), and Massimiliano Brolli (TIM Security Red Team Research, TIM S.p.A) for reporting this issue.
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