CVE-2026-54690 in datamodel-code-generator
Summary
by MITRE • 07/29/2026
datamodel-code-generator generates Pydantic v2 models, dataclasses, TypedDict, and msgspec.Struct from OpenAPI, JSON Schema, GraphQL, Avro, Protobuf, and raw JSON, YAML, or CSV. From 0.9.1 until 0.61.0, datamodel-code-generator silently dereferences attacker-controlled JSON Schema $ref HTTP or HTTPS URLs in src/datamodel_code_generator/parser/jsonschema.py through _get_ref_body, and the --allow-remote-refs gate can warn instead of blocking, allowing server-side request forgery through src/datamodel_code_generator/http.py. This issue is fixed in version 0.61.0.
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Analysis
by VulDB Data Team • 07/29/2026
The datamodel-code-generator tool presents a critical server-side request forgery vulnerability that affects versions ranging from 0.9.1 through 0.61.0. This vulnerability stems from the tool's automated processing of JSON Schema references, specifically when handling remote $ref URLs during model generation workflows. The flaw exists in the core parsing logic within src/datamodel_code_generator/parser/jsonschema.py where the _get_ref_body function performs silent dereferencing of attacker-controlled HTTP or HTTPS URLs without proper validation or restriction mechanisms. The vulnerability becomes particularly dangerous because the tool's default behavior silently processes these remote references, making detection difficult for users who may unknowingly expose their systems to external network requests during code generation operations.
The technical implementation of this vulnerability demonstrates poor input validation and insecure remote reference handling practices that align with CWE-918 Server-Side Request Forgery. The issue manifests through the tool's HTTP processing module in src/datamodel_code_generator/http.py where the --allow-remote-refs configuration option fails to provide adequate protection mechanisms, instead offering only warning capabilities rather than robust blocking of malicious URL references. This design flaw allows attackers to craft malicious JSON Schema documents containing carefully constructed $ref entries pointing to internal network resources or external malicious endpoints, potentially enabling reconnaissance activities or further exploitation. The vulnerability operates at the parsing layer where legitimate code generation workflows become vectors for unauthorized network activity.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to perform network-based reconnaissance against internal systems that may be accessible from the machine running datamodel-code-generator. An attacker could construct a malicious schema document with $ref entries pointing to internal services such as databases, web applications, or other sensitive systems, potentially allowing them to determine which services are available on internal networks or even exfiltr data through carefully crafted references. The silent nature of this vulnerability means that system administrators may not immediately detect unauthorized network activity occurring during legitimate code generation processes, creating a stealthy attack vector that could persist undetected for extended periods.
Security mitigations for this vulnerability should focus on implementing strict reference validation controls and mandatory user consent for remote reference resolution. The fix implemented in version 0.61.0 addresses the core issue by properly restricting remote reference processing and ensuring that users must explicitly enable potentially dangerous behavior rather than having it enabled by default. Organizations should also implement network segmentation and firewall rules to limit outbound connections from systems running code generation tools, while monitoring for unusual network activity patterns during automated build processes. The vulnerability demonstrates the importance of secure coding practices in data processing tools and highlights the need for careful validation of external inputs in schema-based code generation workflows. This issue serves as a reminder that even seemingly benign development tools can present significant security risks when they handle remote references without proper access controls and validation mechanisms, making it a prime example of how insecure defaults can create persistent security vulnerabilities in widely-used software components.