CVE-2025-67858 in Foomuuri
Summary
by MITRE • 01/08/2026
A Improper Neutralization of Argument Delimiters vulnerability in Foomuuri can lead to integrity loss of the firewall configuration or further unspecified impact by manipulating the JSON configuration passed to `nft`. This issue affects Foomuuri: from ? before 0.31.
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Analysis
by VulDB Data Team • 01/09/2026
The vulnerability identified as CVE-2025-67858 represents a critical improper neutralization of argument delimiters flaw within the Foomuuri firewall management system. This weakness specifically manifests when the application processes JSON configuration data that is subsequently passed to the nft command-line tool used for managing netfilter rules. The vulnerability stems from insufficient input validation and sanitization of argument delimiters within the JSON configuration structure, creating potential attack vectors that could compromise firewall integrity and overall system security. The affected version range indicates that all installations prior to version 0.31 remain vulnerable to this exploitation.
The technical implementation of this vulnerability allows attackers to manipulate JSON configuration parameters that are directly translated into nft command arguments. When Foomuuri processes these configurations without proper sanitization of delimiter characters, malicious inputs can inject additional arguments or modify existing command structures. This improper handling creates a path for command injection attacks where attacker-controlled data can alter the intended behavior of the nft utility. The vulnerability falls under CWE-74 which specifically addresses improper neutralization of special elements used in argument lists, making it a direct descendant of well-known input validation weaknesses. The flaw essentially permits an attacker to bypass normal configuration parsing and execution mechanisms, potentially leading to unauthorized modification of firewall rules or complete system compromise.
The operational impact of CVE-2025-67858 extends beyond simple configuration manipulation as it fundamentally undermines the security posture of systems relying on Foomuuri for network protection. An attacker exploiting this vulnerability could potentially modify firewall rules to allow unauthorized network access, block legitimate traffic, or even escalate privileges within the system. The unspecified impact mentioned in the description suggests that the consequences could be far-reaching and may include complete system compromise or data exfiltration. This vulnerability aligns with ATT&CK technique T1059.008 which covers command and scripting interpreter: json, indicating that attackers can leverage JSON-based command execution to perform malicious activities. The potential for integrity loss in firewall configuration means that network security policies could be silently undermined without detection, creating persistent backdoors or weakening overall network defenses.
Organizations utilizing Foomuuri should immediately implement mitigations including upgrading to version 0.31 or later where the vulnerability has been addressed. The fix should include comprehensive input validation and sanitization of all JSON configuration parameters before they are processed and passed to nft commands. Additional defensive measures should encompass monitoring for unusual configuration changes, implementing strict access controls for configuration management interfaces, and conducting regular security audits of firewall rules. Network segmentation and least privilege principles should be enforced to limit potential damage from successful exploitation attempts. Security teams should also consider implementing automated vulnerability scanning tools that can detect improper delimiter handling in configuration management systems and establish incident response procedures specifically addressing firewall configuration integrity breaches. The vulnerability demonstrates the critical importance of proper input sanitization in security-critical applications and highlights the need for robust validation mechanisms in all components that process external configuration data.