CVE-2026-84828VulnerabilityPublished 09/10/2026Updated 10/17/2026

A flaw was found in PCS (Pacemaker Configuration System). (CVE-2026-84828)

Affects pcsSource GCVE Database

ghsa-5g5g-4cqv-r2jw

Not known to be exploited · CVSS 6.5 Medium.

Data as of 10/25/2026, 16:58:57 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Changed
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wild: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
GitHubclusterlabs/pcs`pkg:github/clusterlabs/pcs`Other threats	Affected >=0.10.8	Fixed in–
Ubuntu:Pro:22.04:LTSpcs`pkg:deb/ubuntu/pcs?arch=source&distro=esm-apps/jammy`Other threats	Affected =0.10.8-1ubuntu1 =0.10.11-2ubuntu2 =0.10.11-2ubuntu3 =0.10.11-2ubuntu3+esm1	Fixed in–
Ubuntu:24.04:LTSpcs`pkg:deb/ubuntu/pcs?arch=source&distro=noble`Other threats	Affected =0.11.6-1ubuntu1 =0.11.7-1ubuntu1	Fixed in–
Ubuntu:26.04:LTSpcs`pkg:deb/ubuntu/pcs?arch=source&distro=resolute`Other threats	Affected =0.12.1-2ubuntu1 =0.12.1-2ubuntu3	Fixed in–
Ubuntu:26.10pcs`pkg:deb/ubuntu/pcs?arch=source&distro=stonking`Other threats	Affected =0.12.1-2ubuntu3 =0.12.2-2ubuntu1	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Restrict membership of the 'haclient' group to trusted users only to reduce the attack surface.

Description

A vulnerability in the Pacemaker Configuration System (PCS) allows a local attacker with membership in the 'haclient' group to read arbitrary files shorter than 256 bytes using the 'pcs host auth --token' command. This can lead to disclosure of sensitive information such as API keys and configuration secrets. The flaw affects PCS versions from 0.10.8 onwards, including those shipped with RHEL 8.4+, 9.0+, and 10.0+. Exploitation requires local access and privileged group membership, limiting the attack scope. Mitigation involves restricting 'haclient' group membership to trusted users.

Impact

An attacker with local access and membership in the 'haclient' group can read sensitive files under 256 bytes, potentially exposing API keys and configuration secrets. This can lead to unauthorized disclosure of sensitive information within the cluster environment. The vulnerability does not allow integrity or availability impact, only confidentiality is affected.

Weaknesses

CWE-732Incorrect Permission Assignment for Critical Resource (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
Implementation
When using a critical resource such as a configuration file, check to see if the resource has insecure permissions (such as being modifiable by any regular user), and generate an error or even exit the software if there is a possibility that the resource could have been modified by an unauthorized party.
Architecture and Design
Divide the software into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully defining distinct user groups, privileges, and/or roles. Map these against data, functionality, and the related resources. Then set the permissions accordingly.
Architecture and Design · Operation · Sandbox or Jail
Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software.
OWASP Cheat Sheets
REST Assessment (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V4.3.3 (opens in a new tab)
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
Directory Indexing (opens in a new tab)
Using Malicious Files (opens in a new tab)
Exploiting Incorrectly Configured Access Control Security Levels (opens in a new tab)
Signing Malicious Code (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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