CVE-2026-55391

Name of the Vulnerable Software and Affected Versions datamodel-code-generator versions prior to 0.63.0

Description A server-side request forgery (SSRF) exists due to a time-of-check/time-of-use (TOCTOU) gap during DNS resolution. The software validates the resolved IP of a fetch target to block private or link-local addresses, but it does not pin this result. Consequently, the httpx library performs a second, independent DNS resolution to establish the connection. An attacker can use DNS rebinding—where a hostname resolves to a public IP during validation and a private IP during connection—to bypass the allow private network=False guard. This allows access to internal services, loopback addresses, and cloud-metadata endpoints such as 169.254.169.254. The issue is reachable when the tool fetches an attacker-influenced URL via the --url parameter or a remote $ref in a schema. The vulnerability involves the get body(), validate url for fetch(), and get ips from host() functions within the src/datamodel code generator/http.py file.

Recommendations Update datamodel-code-generator to version 0.63.0 or later.