CVE-2025-6019: libblockdev Privilege Escalation Flaw

CVE-2025-6019 Overview

A Local Privilege Escalation (LPE) vulnerability was found in libblockdev. Generally, the "allow_active" setting in Polkit permits a physically present user to take certain actions based on the session type. Due to the way libblockdev interacts with the udisks daemon, an "allow_active" user on a system may be able to escalate to full root privileges on the target host. Normally, udisks mounts user-provided filesystem images with security flags like nosuid and nodev to prevent privilege escalation. However, a local attacker can create a specially crafted XFS image containing a SUID-root shell, then trick udisks into resizing it. This mounts their malicious filesystem with root privileges, allowing them to execute their SUID-root shell and gain complete control of the system.

Critical Impact
This vulnerability allows local users to gain root privileges on affected systems by exploiting the udisks service in combination with libblockdev.

Affected Products

Not Available
Not Available
Not Available

Discovery Timeline

Not Available - Vulnerability discovered by Not Available
Not Available - Responsible disclosure to Not Available
Not Available - CVE CVE-2025-6019 assigned
Not Available - Not Available releases security patch
2025-06-19T12:15:19.727 - CVE CVE-2025-6019 published to NVD
2025-07-10T14:15:26.630 - Last updated in NVD database

Technical Details for CVE-2025-6019

Vulnerability Analysis

The vulnerability exploits the interaction between libblockdev and udisks, enabling a user with "allow_active" Polkit permissions to execute arbitrary code with root privileges.

Root Cause

The flaw arises from inadequate enforcement of security flags by udisks when resizing filesystems, allowing the execution of setuid programs.

Attack Vector

Local

// Example exploitation code (sanitized)
#include <stdio.h>
#include <stdlib.h>

int main() {
    // Craft a malicious XFS image
    system("dd if=/dev/zero of=malicious.img bs=1M count=10");
    // Trick udisks into mounting it with root privileges
    system("udisksctl mount -b /dev/fake");
    return 0;
}

Detection Methods for CVE-2025-6019

Indicators of Compromise

Unexpected SUID binaries
Unauthorized changes in filesystem permissions
Presence of crafted filesystem images

Detection Strategies

Implement file integrity monitoring and conduct regular audits of mounted filesystems for unauthorized SUID binaries.

Monitoring Recommendations

Utilize SentinelOne’s behavioral AI capabilities to detect unusual filesystem mount activities and privilege escalation attempts.

How to Mitigate CVE-2025-6019

Immediate Actions Required

Immediately unmount any suspicious filesystems
Revoke "allow_active" permissions for unnecessary users
Conduct a security audit of active sessions

Patch Information

Refer to RedHat errata for official patches: RedHat Synopsys Security Advisory

Workarounds

Disable untrusted filesystems and secure udisks configuration to enforce proper mount flags.

bash

# Configuration example
echo "Disallow untrusted mount operations" > /etc/polkit-1/rules.d/10-udisks.rules