CVE-2025-6018 is a Local Privilege Escalation (LPE) vulnerability identified in the pam-config component of Linux Pluggable Authentication Modules (PAM). PAM is a critical authentication framework used by many Linux distributions to manage user authentication and authorization. This specific flaw arises from incorrect authorization logic within pam-config, which improperly grants elevated privileges to unprivileged local users. Normally, certain Polkit actions requiring "allow_active" users are restricted to physically present console users. However, due to this vulnerability, an attacker logged in remotely via SSH or other local access methods can bypass these restrictions and gain the elevated privileges typically reserved for console users. This enables the attacker to perform all Polkit actions allowed for "allow_active yes" users, which can include modifying system configurations, managing services, and executing other sensitive operations that could compromise system integrity and confidentiality. The vulnerability has a CVSS 3.1 base score of 7.8, indicating high severity. The attack vector is local (AV:L), requiring low attack complexity (AC:L) and low privileges (PR:L), with no user interaction (UI:N) needed. The impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). Although no known exploits are currently reported in the wild, the vulnerability presents a significant risk due to the broad scope of privileged actions accessible upon exploitation. The affected versions are not explicitly detailed beyond "0", suggesting it may impact default or initial versions of pam-config or PAM modules incorporating this component. The flaw was reserved in June 2025 and published in July 2025, with Red Hat as the assigner, indicating that major Linux distributions using PAM are likely affected. No patch links are provided yet, so mitigation may rely on configuration changes or vendor updates once available.

For European organizations, this vulnerability poses a substantial risk, especially for enterprises relying on Linux servers for critical infrastructure, cloud services, and internal IT systems. Successful exploitation allows an attacker with local access—such as a compromised user account or an attacker who gains SSH access—to escalate privileges and perform administrative tasks without proper authorization. This can lead to unauthorized changes in system configurations, service disruptions, data breaches, and potential lateral movement within networks. Given the widespread use of PAM across various Linux distributions common in Europe (e.g., Red Hat Enterprise Linux, CentOS, Debian, Ubuntu), the vulnerability could affect a broad range of sectors including finance, healthcare, government, and telecommunications. The ability to bypass Polkit restrictions undermines trust in system security controls and could facilitate further attacks such as deploying malware, exfiltrating sensitive data, or disabling security mechanisms. The lack of user interaction and low complexity of exploitation increase the likelihood of successful attacks once local access is obtained. Organizations with remote access policies or multi-user environments are particularly at risk. Additionally, the vulnerability could be leveraged in targeted attacks against high-value assets or critical infrastructure within Europe, amplifying its potential impact.

Immediate mitigation should focus on restricting local access to trusted users only, enforcing strong authentication mechanisms for SSH and other remote access methods, and monitoring for unusual privilege escalation attempts. Organizations should audit current PAM configurations and Polkit policies to identify and limit the use of "allow_active" settings where possible. Applying principle of least privilege to user accounts and disabling unnecessary services can reduce the attack surface. Since no official patches are currently linked, organizations should stay alert for vendor advisories and promptly apply updates once available. In the interim, consider implementing additional access controls such as mandatory multi-factor authentication (MFA) for local and remote logins, and enhanced logging and alerting on Polkit actions. Employing host-based intrusion detection systems (HIDS) to detect anomalous privilege escalations can provide early warning. Network segmentation to isolate critical systems and limiting SSH access via jump hosts or bastion servers can further reduce risk. Finally, conducting regular security assessments and penetration tests focusing on privilege escalation vectors will help identify and remediate exposure to this vulnerability.