CVE-2026-84828: Pcs: pcs: non-root haclient users can read arbitrary files via pcs host auth --token

Vulnerability summary

CVE-2026-84828 is a medium (CVSS 6.5) vulnerability in pcs. EPSS estimates a 0.14% chance of exploitation in the next 30 days, higher than 3.5% of scored vulnerabilities.

Timeline

1. 10-09-2026
   PublishedVulnerability first disclosed.
2. 14-09-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in PCS (Pacemaker Configuration System). A local attacker with membership in the 'haclient' group can exploit the 'pcs host auth --token' command to read the contents of arbitrary files on the filesystem, provided the files are shorter than 256 bytes. The file contents are read with root privileges by the pcsd daemon and can be exfiltrated by the attacker through subsequent cluster node communication. This allows disclosure of sensitive data such as API keys, tokens, or configuration secrets that would otherwise be inaccessible to the attacker.

• CWE-732Incorrect Permission Assignment for Critical ResourceThe product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.