CVE-2025-6018: 
Linux openSUSE vulnerability analysis and mitigation

A Local Privilege Escalation (LPE) vulnerability has been discovered in pam-config within Linux Pluggable Authentication Modules (PAM). This flaw (CVE-2025-6018) was discovered in May 2025 and affects openSUSE Leap 15 and SUSE Linux Enterprise 15 systems. The vulnerability allows an unprivileged local attacker (for example, a user logged in via SSH) to obtain the elevated privileges normally reserved for a physically present, 'allowactive' user ([SUSE Bugzilla](https://bugzilla.suse.com/showbug.cgi?id=1243226), Qualys Advisory).

The vulnerability exists in PAM's pamenv module (from Linux-PAM 1.3.0) where the 'userreadenv' configuration option is enabled by default. When an unprivileged user logs in via SSH, the pamenv module reads the user's ~/.pamenvironment file as part of PAM's 'auth' stack, followed by the pamsystemd module being called later in the 'session' stack. This allows attackers to inject arbitrary variables into PAM's environment by writing to ~/.pamenvironment, which are then processed by the pamsystemd module. The vulnerability has been assigned a CVSS v3.1 base score of 7.8 (HIGH) with vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (NVD, [Red Hat Bugzilla](https://bugzilla.redhat.com/showbug.cgi?id=2372693)).

The vulnerability allows attackers to perform all 'allowactive yes' polkit actions typically restricted to console users. This could lead to unauthorized control over system configurations, services, and other sensitive operations. By setting XDGSEAT=seat0 and XDGVTNR=1 in ~/.pamenvironment, an attacker can impersonate a physical user and gain elevated privileges (Qualys Advisory).

System administrators should immediately apply vendor patches. SUSE has issued updates for both vulnerabilities, and additional guidance is available through Linux distribution security advisories. The recommended mitigation includes disabling userreadenv in PAM configurations (pamenv), especially in /etc/pam.d/sshd, auditing and limiting polkit actions granted to 'allow_active' users, and monitoring systems for unexpected loop device mounts under /tmp (SOCRadar).

The security community has shown significant concern about this vulnerability, particularly due to its potential for privilege escalation. The issue has gained attention on platforms like Hacker News and security blogs, with researchers highlighting its significance in the context of Linux system security. Security experts emphasize the importance of prompt patching, especially given the vulnerability's relatively simple exploitation method (SOCRadar).