CWE-610 Class Draft

Externally Controlled Reference to a Resource in Another Sphere

This vulnerability occurs when an application uses user-supplied input to reference a resource located outside its intended security boundary, allowing attackers to redirect operations to unintended…

Definition

What is CWE-610?

This vulnerability occurs when an application uses user-supplied input to reference a resource located outside its intended security boundary, allowing attackers to redirect operations to unintended locations.
This flaw typically happens when developers treat all resource identifiers (like filenames, URLs, or keys) as safe, even when they come from untrusted sources like user input, configuration files, or API responses. Attackers exploit this by injecting paths or references that "escape" the application's intended directory, server, or cloud environment—often using sequences like `../` to traverse directories or full URLs to external systems. The core issue is a failure to validate that a referenced resource actually resides within the allowed security sphere before accessing it. To prevent this, always validate and sanitize all resource references against an allow-list of permitted locations. Implement strict access controls and use mechanisms like chroot jails, container boundaries, or signed URLs to enforce isolation. Never rely solely on input filtering; instead, design your system to map user-provided identifiers to actual resources through an indirect reference map or lookup table that you fully control.
Real-world impact

Real-world CVEs caused by CWE-610

  • CVE-2022-3032

    An email client does not block loading of remote objects in a nested document.

  • CVE-2022-45918

    Chain: a learning management tool debugger uses external input to locate previous session logs (CWE-73) and does not properly validate the given path (CWE-20), allowing for filesystem path traversal using "../" sequences (CWE-24)

  • CVE-2018-1000613

    Cryptography API uses unsafe reflection when deserializing a private key

  • CVE-2020-11053

    Chain: Go-based Oauth2 reverse proxy can send the authenticated user to another site at the end of the authentication flow. A redirect URL with HTML-encoded whitespace characters can bypass the validation (CWE-1289) to redirect to a malicious site (CWE-601)

  • CVE-2022-42745

    Recruiter software allows reading arbitrary files using XXE

  • CVE-2004-2331

    Database system allows attackers to bypass sandbox restrictions by using the Reflection API.

How attackers exploit it

Step-by-step attacker path

  1. 1

    The following code is a Java servlet that will receive a GET request with a url parameter in the request to redirect the browser to the address specified in the url parameter. The servlet will retrieve the url parameter value from the request and send a response to redirect the browser to the url address.

  2. 2

    The problem with this Java servlet code is that an attacker could use the RedirectServlet as part of an e-mail phishing scam to redirect users to a malicious site. An attacker could send an HTML formatted e-mail directing the user to log into their account by including in the e-mail the following link:

  3. 3

    The user may assume that the link is safe since the URL starts with their trusted bank, bank.example.com. However, the user will then be redirected to the attacker's web site (attacker.example.net) which the attacker may have made to appear very similar to bank.example.com. The user may then unwittingly enter credentials into the attacker's web page and compromise their bank account. A Java servlet should never redirect a user to a URL without verifying that the redirect address is a trusted site.

Vulnerable code example

Vulnerable Java

The following code is a Java servlet that will receive a GET request with a url parameter in the request to redirect the browser to the address specified in the url parameter. The servlet will retrieve the url parameter value from the request and send a response to redirect the browser to the url address.

Vulnerable Java 
public class RedirectServlet extends HttpServlet {
  		protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  			String query = request.getQueryString();
  			if (query.contains("url")) {
  				String url = request.getParameter("url");
  				response.sendRedirect(url);
  			}
  		}
  }
Attacker payload

The problem with this Java servlet code is that an attacker could use the RedirectServlet as part of an e-mail phishing scam to redirect users to a malicious site. An attacker could send an HTML formatted e-mail directing the user to log into their account by including in the e-mail the following link:

Attacker payload HTML 
<a href="http://bank.example.com/redirect?url=http://attacker.example.net">Click here to log in</a>
Secure code example

Secure pseudo

Secure pseudo 
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist

How to prevent CWE-610

  • Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
  • Implementation Validate input at trust boundaries; use allowlists, not denylists.
  • Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
  • Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
  • Operation Monitor logs for the runtime signals listed in the next section.
Detection signals

How to detect CWE-610

SAST High

Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.

DAST Moderate

Run dynamic application security testing against the live endpoint.

Runtime Moderate

Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.

Code review Moderate

Code review: flag any new code that handles input from this surface without using the validated framework helpers.

Plexicus auto-fix

Plexicus auto-detects CWE-610 and opens a fix PR in under 60 seconds.

Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.

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Frequently asked questions

Frequently asked questions

What is CWE-610?

This vulnerability occurs when an application uses user-supplied input to reference a resource located outside its intended security boundary, allowing attackers to redirect operations to unintended locations.

How serious is CWE-610?

MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.

What languages or platforms are affected by CWE-610?

MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.

How can I prevent CWE-610?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

How does Plexicus detect and fix CWE-610?

Plexicus's SAST engine matches the data-flow signature for CWE-610 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.

Where can I learn more about CWE-610?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/610.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-610

CWE-664 Parent

Improper Control of a Resource Through its Lifetime

This vulnerability occurs when software fails to properly manage a resource throughout its entire lifecycle—from creation and active use…

CWE-118 Sibling

Incorrect Access of Indexable Resource ('Range Error')

This vulnerability occurs when software fails to properly check the boundaries of an indexed resource, like an array, buffer, or file,…

CWE-1229 Sibling

Creation of Emergent Resource

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CWE-1250 Sibling

Improper Preservation of Consistency Between Independent Representations of Shared State

This vulnerability occurs when a system with multiple independent components (like distributed services or separate hardware units) each…

CWE-1329 Sibling

Reliance on Component That is Not Updateable

This vulnerability occurs when a product depends on a component that cannot be updated or patched to fix security flaws or critical bugs.

CWE-221 Sibling

Information Loss or Omission

This weakness occurs when an application fails to log critical security events or records them inaccurately, which can misguide security…

CWE-372 Sibling

Incomplete Internal State Distinction

This vulnerability occurs when an application fails to accurately track its own operational state. The system incorrectly assumes it's in…

CWE-400 Sibling

Uncontrolled Resource Consumption

This vulnerability occurs when an application fails to properly manage a finite resource, allowing an attacker to exhaust it and cause a…

CWE-404 Sibling

Improper Resource Shutdown or Release

This vulnerability occurs when a program fails to properly close or release a system resource—like a file handle, database connection, or…

Resources

Further reading

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