CVE-2019-12384 in jackson-databind
Summary
by MITRE
FasterXML jackson-databind 2.x before 2.9.9 might allow attackers to have a variety of impacts by leveraging failure to block the logback-core class from polymorphic deserialization. Depending on the classpath content, remote code execution may be possible.
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Analysis
by VulDB Data Team • 05/17/2025
The vulnerability identified as CVE-2019-12384 affects the FasterXML jackson-databind library version 2.x prior to 2.9.9, representing a critical security flaw in Java applications that utilize this popular data processing library. This issue stems from the library's insufficient validation mechanisms during polymorphic deserialization processes, which creates a pathway for attackers to exploit the system through carefully crafted malicious input data. The vulnerability specifically targets the failure to properly block the logback-core class from being deserialized, a scenario that can be leveraged to execute arbitrary code on affected systems.
The technical flaw manifests through the library's handling of polymorphic deserialization, where objects are deserialized based on their runtime type rather than their declared type. This capability, while useful for legitimate applications, becomes dangerous when combined with the absence of proper class validation. When the jackson-databind library encounters serialized data containing references to classes from the logback-core package, it fails to implement adequate safeguards to prevent deserialization of potentially malicious classes. This failure creates a vector for remote code execution attacks, particularly when the affected application has logback-core classes available in its classpath, as the library can be tricked into executing arbitrary code through the deserialization process.
The operational impact of this vulnerability extends beyond simple data corruption or denial of service scenarios, as it can enable full system compromise when exploited successfully. Attackers can leverage this vulnerability to execute arbitrary commands on the target system, potentially gaining complete control over the affected application server. The severity is amplified by the widespread adoption of jackson-databind across numerous enterprise applications and frameworks, meaning that a single vulnerable component can affect multiple systems within an organization. The attack surface is particularly broad since many applications that use jackson-databind are exposed to untrusted input from external sources, making the exploitation relatively straightforward for skilled attackers.
The vulnerability aligns with CWE-502, which describes "Deserialization of Untrusted Data" as a fundamental weakness in software security. This classification emphasizes the critical nature of validating and sanitizing serialized data before processing, particularly when dealing with polymorphic objects that can be resolved to different types at runtime. From an attacker's perspective, this vulnerability maps to multiple techniques in the MITRE ATT&CK framework, specifically targeting the execution and privilege escalation phases through code injection and remote command execution capabilities. Organizations should implement immediate mitigations including upgrading to jackson-databind version 2.9.9 or later, implementing proper class validation mechanisms, and restricting deserialization access to only trusted classes. Additionally, network segmentation and input validation controls can provide additional layers of defense against exploitation attempts.
The remediation approach requires organizations to conduct comprehensive vulnerability assessments across their application portfolios to identify all instances of the vulnerable jackson-databind library. This assessment should include not only direct dependencies but also transitive dependencies that may pull in the vulnerable version. System administrators should prioritize patching efforts, as the vulnerability is considered high-risk due to its potential for remote code execution. Organizations may also consider implementing application firewalls or intrusion detection systems that can monitor for suspicious deserialization patterns, providing additional protection against exploitation attempts. The incident highlights the importance of maintaining up-to-date dependencies and implementing proper security controls around data processing libraries that handle untrusted input.