Critical Race Conditions in Linux Core Dump Systems Expose Sensitive Data to Local Attackers

Cybersecurity researchers at Qualys have uncovered two significant security flaws affecting core dump handling mechanisms in major Linux distributions, potentially allowing local attackers to access confidential system information through sophisticated race condition exploits.

Vulnerability Overview

The discovered security issues impact crash reporting and core dump processing systems used across Ubuntu, Red Hat Enterprise Linux, and Fedora distributions. Both vulnerabilities stem from race condition defects in fundamental Linux system components responsible for handling application crashes and generating diagnostic information.

CVE-2025-5054 affects Canonical's apport package (versions up to 2.32.0) with a CVSS severity rating of 4.7. This flaw enables local attackers to exploit PID reuse mechanisms through namespace manipulation to extract sensitive information from privileged processes.

CVE-2025-4598 targets systemd-coredump functionality, also rated at CVSS 4.7 severity. This vulnerability allows attackers to manipulate SUID process crashes and substitute them with unprivileged binaries, gaining unauthorized access to the original privileged process's core dump data.

Technical Attack Mechanics

The vulnerabilities exploit the Set User ID (SUID) permission system, which enables programs to execute with elevated privileges beyond the user's normal access level. Attackers can leverage timing vulnerabilities during the brief window when privileged processes crash and core dumps are generated.

For the apport vulnerability, attackers must induce crashes in privileged processes while simultaneously replacing them with malicious processes sharing the same process identifier within mount and PID namespaces. The apport system then forwards the privileged core dump containing sensitive data into the attacker-controlled namespace.

The systemd-coredump exploit follows a similar pattern, where attackers force SUID processes to crash and quickly substitute non-SUID replacements to intercept the original process's core dump information.

Impact and Sensitive Data Exposure

Security researchers have demonstrated proof-of-concept attacks showing how these vulnerabilities can be exploited to extract password hashes from the /etc/shadow file by targeting the unix_chkpwd process, which validates user authentication credentials.

The potential data exposure includes:

• User password hashes and authentication credentials
• Encryption keys and cryptographic material
• Customer information and business data
• System configuration details
• Memory contents from privileged applications

Distribution-Specific Vulnerabilities

The security flaws affect different Linux distributions to varying degrees:

• Ubuntu and Red Hat Enterprise Linux: Vulnerable to both CVE-2025-5054 and CVE-2025-4598
• Fedora: Affected by both vulnerabilities
• Debian: Not vulnerable to CVE-2025-4598 by default unless systemd-coredump is manually installed
• Amazon Linux and Gentoo: Have issued security advisories addressing these issues

Mitigation Strategies

Red Hat has provided immediate mitigation guidance for administrators concerned about exploitation risks. The primary recommended workaround involves disabling SUID core dump generation entirely by executing:

echo 0 > /proc/sys/fs/suid_dumpable

This command prevents SUID programs from generating core dumps following crashes, effectively blocking the attack vector. However, this mitigation comes with operational trade-offs, as it also disables legitimate crash analysis capabilities for SUID binaries.

Exploitation Complexity and Risk Assessment

Despite the moderate CVSS scores, security experts note that successful exploitation requires significant technical sophistication. Attackers must:

• Possess local system access
• Successfully manipulate race conditions with precise timing
• Have detailed knowledge of system process behavior
• Win the race condition against normal system operations

Red Hat characterizes the exploitation complexity as "high," which somewhat reduces the immediate risk level for most organizations.

Vendor Response and Remediation

Canonical acknowledges that while the apport vulnerability can expose SUID executable memory spaces, the practical real-world impact of password hash extraction remains limited. The company emphasizes that the confidentiality impact is restricted to specific memory regions of privileged processes.

Multiple Linux distribution vendors have released security advisories and are working on comprehensive patches to address these race condition vulnerabilities in their respective core dump handling systems.

Enterprise Security Recommendations

Qualys security researchers emphasize that despite the technical complexity required for exploitation, these vulnerabilities pose significant confidentiality risks for enterprise environments. Successful attacks could result in:

• Operational service disruptions
• Reputational damage from data breaches
• Regulatory compliance violations
• Exposure of critical business information

Organizations should implement comprehensive security measures including prioritized patching schedules, enhanced system monitoring, and stricter access control policies to mitigate these multifaceted security risks effectively.