Description

MegaParse 0.0.55 contains an unauthenticated server-side request forgery vulnerability in the POST /v1/url endpoint that fetches caller-supplied URLs server-side. Attackers can supply internal service URLs or metadata endpoints without authentication to read their responses directly from the JSON response.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.5",
  "pubDate": "2026-09-04T15:17:47.097Z",
  "pubdate": "2026-09-04T15:17:47.097Z",
  "executiveSummary": "MegaParse version 0.0.55 is susceptible to an unauthenticated Server-Side Request Forgery (SSRF) vulnerability residing within the POST /v1/url endpoint.\nThe vulnerability allows remote, unauthenticated attackers to force the application server to perform arbitrary HTTP requests to internal or external resources.\nBy manipulating the URL parameter, an adversary can interact with sensitive internal network services, private APIs, or cloud provider metadata endpoints (e.g., 169.254.169.254).\nBecause the application directly returns the response body of the fetched URL in the JSON output, the flaw facilitates sensitive data exfiltration and potential reconnaissance of internal infrastructure.\nThe risk is critical due to the lack of authentication, allowing full exploitation by any actor capable of reaching the service. Successful exploitation grants the attacker the ability to bypass network segmentation and interact with services that are otherwise shielded from the public internet.\nImpact includes unauthorized information disclosure, scanning of internal network topology, and potential interaction with cloud-based identity and access management (IAM) credentials.",
  "technicalDetails": "The vulnerability is situated within the MegaParse v0.0.55 application's request processing logic at the /v1/url endpoint. The root cause is a failure to implement proper input validation or allowlisting mechanisms for user-supplied URLs passed to the server-side fetching module.\nThe component responsible for initiating the outgoing request does not verify the destination's network address, allowing it to reach loopback (127.0.0.1), link-local (169.254.169.254), or non-routable private CIDR ranges (RFC 1918).\nThe attack flow begins when an attacker sends a POST request to /v1/url containing a crafted URL parameter. The application processes this request by initiating an outbound HTTP/HTTPS request to the specified target. Because the backend environment typically trusts requests originating from 'localhost' or within the VPC, the target service may bypass standard authentication protocols.\nUpon receiving a response from the targeted internal resource, the MegaParse server encapsulates the raw data into its own JSON response object and returns it to the attacker. This mechanism provides a direct feedback loop, allowing the attacker to read the contents of restricted internal files, system configuration endpoints, or service discovery pages.\nFor example, an attacker could target a cloud metadata service endpoint to retrieve instance identity documents or IAM role security credentials. Similarly, an attacker could target internal management consoles, databases, or Redis caches that rely on IP-based security models rather than application-level authentication.\nThe vulnerability is exposed via the public network interface, requiring no authentication or prior authorization to access the /v1/url endpoint. There are no known privilege constraints, as the exploitation context inherits the permissions and network reachability of the MegaParse process itself. Post-exploitation impact is limited only by the network visibility of the server hosting MegaParse and the specific security configurations of the internal services being probed."
}