CVE-2025-6019: 
Alma Linux vulnerability analysis and mitigation

CVE-2025-6019 is a Local Privilege Escalation (LPE) vulnerability discovered in libblockdev that can be exploited via the udisks daemon. The vulnerability was discovered by Qualys researchers and disclosed on June 17, 2025. The issue affects most Linux distributions including Ubuntu, Debian, Fedora, and openSUSE Leap 15, where libblockdev and udisks are installed by default (Qualys Advisory).

The vulnerability exists in libblockdev's handling of mount options when resizing XFS filesystems. When an XFS filesystem resize is requested through udisks, libblockdev temporarily mounts the filesystem in /tmp without the nosuid and nodev flags. This oversight allows an attacker with 'allow_active' privileges to mount a specially crafted XFS image containing a SUID-root shell, which can then be executed to obtain root privileges. The vulnerability is particularly concerning because udisks is included by default on most Linux distributions (Help Net Security, Ubuntu Blog).

When successfully exploited, this vulnerability allows a local attacker with 'allow_active' privileges (typically a user with physical console access) to escalate their privileges to root. Once root access is achieved, an attacker can disable EDR agents, implant backdoors, modify system configurations, and potentially use the compromised system as a launchpad for wider organizational compromise (Help Net Security).

Patches have been released for affected distributions. Ubuntu has released updates for all supported versions, including 18.04 LTS through 25.04. The recommended mitigation is to apply the security updates immediately. If updates cannot be applied immediately, a temporary workaround involves modifying the polkit rule for org.freedesktop.udisks2.modify-device in /usr/share/polkit-1/actions/org.freedesktop.UDisks2.policy to change allowactive from 'yes' to 'authadmin' (Ubuntu Blog).

Security experts emphasize the critical nature of this vulnerability, particularly when chained with other vulnerabilities like CVE-2025-6018. Saeed Abbasi, Senior Manager at Qualys, stated that 'these modern local-to-root exploits have collapsed the gap between an ordinary logged-in user and a full system takeover' and advised organizations to 'treat this as a critical, universal risk and deploy patches without delay' (Help Net Security).