CVE-2025-11226: Medium Vulnerability in QOS.CH Logback-Core

CVE-2025-11226 is identified as a medium-severity ACE vulnerability in the conditional configuration file processing of QOS.CH Logback-Core, applicable to versions 1.5.18 and earlier in Java applications. This vulnerability allows an attacker to execute arbitrary code by either compromising an existing logback configuration file or by injecting a malicious environment variable prior to program execution. The potential for exploit requires specific conditions to be met.

Specifically, a successful attack necessitates the presence of the Janino library and the Spring Framework on the user's class path. Moreover, the attacker must have write access to a configuration file. Alternatively, the attacker could inject an environment variable that points to a malicious configuration file. In both scenarios, existing privileges would be required for the attack to be successful.

The CVSS score for this vulnerability is 5.9, indicating a medium severity level. Organizations utilizing affected versions of Logback-Core should take this vulnerability seriously due to the potential risks associated with arbitrary code execution.

Given the nature of this vulnerability and its implications, organizations should address it in their priority patch cycle. The risk to organizations includes exposure to arbitrary code execution, which could lead to further compromise of systems and data.

It is important to note that there is currently no known public exploit or proof of concept for this vulnerability. However, the potential for exploitation remains, and organizations should remain vigilant.

Vulnerability Details

CVE-2025-11226 is classified as an ACE vulnerability, with a CVSS score of 5.9. The vulnerability affects the QOS.CH Logback-Core up to and including version 1.5.18. The publication date for this vulnerability is October 1, 2025. The relevant CWE classification is CWE-20, which corresponds to improper input validation.

Technical Analysis

The root cause of this vulnerability lies in the processing of configuration files by the Logback-Core. Specifically, improper validation allows an attacker to execute arbitrary code if the attacker can modify the configuration file or inject an environment variable. The attack vector is local, meaning that an attacker must have access to the system where the Java application is running.

The attack complexity is low, as it requires minimal effort to either modify a configuration file or set an environment variable. Privileges required are high, meaning the attacker must have administrative permissions to exploit this vulnerability. User interaction is passive, as the attack does not require any action from the user.

The potential impacts of this vulnerability include high confidentiality impact, low integrity impact, and low availability impact. This means that while the attack may compromise sensitive data, it is less likely to affect the integrity or availability of the affected system.

Risk & Impact Analysis

Organizations utilizing affected versions of QOS.CH Logback-Core may face significant risks if this vulnerability is exploited. The arbitrary code execution capability could allow unauthorized access to sensitive data, system modification, or further network compromise. Given that the attacker requires high privileges, the blast radius may be limited to users with elevated access, but the consequences could still be severe.

Given the CVSS score of 5.9, organizations should prioritize addressing this vulnerability in their patch management process. The vulnerability's exploitation could lead to unauthorized actions and significant operational disruptions.

Organizations should schedule remediation for this vulnerability as part of their ongoing security maintenance. Implementing strict access controls and monitoring for unauthorized changes can help mitigate risks associated with this vulnerability.

Exploitation Status

Affected Versions

The affected versions of QOS.CH Logback-Core include all versions up to and including version 1.5.18. Organizations should ensure they upgrade to version 1.5.19 or later to mitigate this vulnerability.

Mitigation & Remediation

Organizations should prioritize patching to version 1.5.19 or later to remediate this vulnerability. In addition, implementing strict access controls on configuration files can help prevent unauthorized modifications.

For those unable to apply patches immediately, consider reviewing and hardening application configurations and monitoring for unauthorized changes. Regular security audits can also help identify potential points of exploitation.

For further guidance on security practices, organizations can refer to our comprehensive resources on application security assessments.

Detection Guidance

Organizations should monitor logs for any unauthorized modifications to configuration files. Additionally, behavioral anomalies in application performance may indicate potential exploitation attempts. Implementing network signatures can also help detect related malicious activities.

AppSecure Threat Intelligence Insight

The existence of CVE-2025-11226 highlights ongoing challenges in the management of configuration files in Java applications. As organizations increasingly rely on frameworks like Spring, the importance of securing these components cannot be overstated.

This vulnerability serves as a reminder of the potential risks associated with improper configuration management. Security teams should be vigilant in applying best practices to mitigate such vulnerabilities.

For further insights into managing vulnerabilities and strengthening security postures, organizations may benefit from exploring our offerings on penetration testing services and our broader approach to security.

Regular engagement in security assessments and vulnerability management programs can empower organizations to better protect their assets against emerging threats.