CVE-2025-66214 is a deserialization vulnerability categorized under CWE-502, affecting the Ladybug tool developed by wearefrank. Ladybug facilitates message-based debugging and testing for Java applications. The vulnerability exists in versions prior to 3.0-20251107.114628, specifically in the APIs /iaf/ladybug/api/report/{storage} and /iaf/ladybug/api/report/upload, which accept gzip-compressed XML files containing user-controlled data. The system deserializes these XML files without sufficient validation or sanitization, enabling attackers to craft malicious XML payloads that trigger remote code execution (RCE) on the server hosting Ladybug. The attack vector requires local network access (AV:L) and low privileges (PR:L), but no user interaction (UI:N) is needed. The vulnerability has a scope change (S:C), meaning it can affect resources beyond the initially vulnerable component. The impact on confidentiality is high, as attackers can potentially access sensitive data; integrity is impacted at a low level, and availability is also affected to a low degree. The vulnerability is rated with a CVSS 3.1 score of 7, indicating high severity. Although no exploits are currently known in the wild, the nature of insecure deserialization makes this a critical risk if left unpatched. The issue is resolved in Ladybug version 3.0-20251107.114628, which should be adopted promptly to mitigate risk.

For European organizations, this vulnerability poses a significant risk, especially for those relying on Ladybug for Java application debugging and testing. Successful exploitation could lead to remote code execution, allowing attackers to gain unauthorized access to internal systems, exfiltrate sensitive data, or disrupt services. This could impact confidentiality by exposing proprietary or personal data, integrity by allowing unauthorized code execution or modification, and availability by potentially causing system crashes or denial of service. Given the vulnerability requires only low privileges and no user interaction, insider threats or attackers with limited access could escalate their control over critical infrastructure. The impact is heightened in sectors with stringent data protection regulations such as GDPR, where breaches can lead to severe legal and financial penalties. Organizations in finance, healthcare, and government sectors are particularly at risk due to the sensitive nature of their data and critical services.

European organizations should immediately upgrade Ladybug to version 3.0-20251107.114628 or later to remediate the vulnerability. Until patching is possible, restrict access to the vulnerable APIs (/iaf/ladybug/api/report/{storage} and /iaf/ladybug/api/report/upload) through network segmentation and firewall rules, limiting them to trusted internal users only. Implement strict input validation and filtering on uploaded XML files to detect and block malicious payloads. Employ runtime application self-protection (RASP) or web application firewalls (WAFs) with custom rules to monitor and block suspicious deserialization attempts. Conduct thorough code reviews and security testing for any custom integrations with Ladybug. Monitor logs for unusual activity related to these endpoints and establish alerting mechanisms for potential exploitation attempts. Additionally, enforce the principle of least privilege for users interacting with Ladybug to minimize the risk of privilege escalation.