CWE-346 Class Draft

Origin Validation Error

This vulnerability occurs when an application fails to properly confirm the true origin of incoming data or communication, allowing attackers to spoof their source.

Definition

What is CWE-346?

This vulnerability occurs when an application fails to properly confirm the true origin of incoming data or communication, allowing attackers to spoof their source.
Origin Validation Errors happen because applications often trust metadata like IP addresses, DNS names, or HTTP headers that can be easily forged. Attackers exploit this by impersonating legitimate systems, tricking the application into accepting malicious data as if it came from a trusted source. This is a fundamental flaw in the trust boundary of the system. To prevent this, developers must implement robust verification mechanisms that rely on unforgeable credentials, such as cryptographic signatures or secure tokens, rather than easily spoofed information. Always validate the origin at the point of trust establishment and consistently enforce this check for all subsequent interactions.
Real-world impact

Real-world CVEs caused by CWE-346

  • CVE-2000-1218

    DNS server can accept DNS updates from hosts that it did not query, leading to cache poisoning

  • CVE-2018-6074

    Browser does not set Mark-of-the-Web (MotW) for a downloaded .EXE file if the name is close to the maximum path length, preventing recording of a zone identifier in the filename

  • CVE-2025-0411

    Zip file extraction program does not propagate Mark-of-the-Web (MotW) metadata to files that are extracted from an Internet-downloaded Zip file

  • CVE-2025-46652

    Zip file extraction program does not propagate Mark-of-the-Web (MotW) metadata to files that are extracted from an Internet-downloaded Zip file

  • CVE-2005-0877

    DNS server can accept DNS updates from hosts that it did not query, leading to cache poisoning

  • CVE-2001-1452

    DNS server caches glue records received from non-delegated name servers

  • CVE-2005-2188

    user ID obtained from untrusted source (URL)

  • CVE-2003-0174

    LDAP service does not verify if a particular attribute was set by the LDAP server

How attackers exploit it

Step-by-step attacker path

  1. 1

    This Android application will remove a user account when it receives an intent to do so:

  2. 2

    This application does not check the origin of the intent, thus allowing any malicious application to remove a user. Always check the origin of an intent, or create an allowlist of trusted applications using the manifest.xml file.

  3. 3

    These Android and iOS applications intercept URL loading within a WebView and perform special actions if a particular URL scheme is used, thus allowing the Javascript within the WebView to communicate with the application:

  4. 4

    A call into native code can then be initiated by passing parameters within the URL:

  5. 5

    Because the application does not check the source, a malicious website loaded within this WebView has the same access to the API as a trusted site.

Vulnerable code example

Vulnerable Java

This Android application will remove a user account when it receives an intent to do so:

Vulnerable Java 
IntentFilter filter = new IntentFilter("com.example.RemoveUser");
  MyReceiver receiver = new MyReceiver();
  registerReceiver(receiver, filter);
  public class DeleteReceiver extends BroadcastReceiver {
  	@Override
  	public void onReceive(Context context, Intent intent) {
  		int userID = intent.getIntExtra("userID");
  		destroyUserData(userID);
  	}
  }
Attacker payload

A call into native code can then be initiated by passing parameters within the URL:

Attacker payload JavaScript 
window.location = examplescheme://method?parameter=value
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-346

  • 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-346

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-346 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-346?

This vulnerability occurs when an application fails to properly confirm the true origin of incoming data or communication, allowing attackers to spoof their source.

How serious is CWE-346?

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-346?

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

How can I prevent CWE-346?

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-346?

Plexicus's SAST engine matches the data-flow signature for CWE-346 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-346?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/346.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-346

CWE-345 Parent

Insufficient Verification of Data Authenticity

This vulnerability occurs when an application fails to properly check where data comes from or confirm its legitimacy, allowing untrusted…

CWE-1293 Sibling

Missing Source Correlation of Multiple Independent Data

This vulnerability occurs when a system trusts a single source of data without verification, making it impossible to detect if that source…

CWE-347 Sibling

Improper Verification of Cryptographic Signature

This vulnerability occurs when an application fails to properly check the digital signature on data, or skips the verification step…

CWE-348 Sibling

Use of Less Trusted Source

This vulnerability occurs when a system has access to multiple sources for the same critical data, but it chooses to rely on the less…

CWE-349 Sibling

Acceptance of Extraneous Untrusted Data With Trusted Data

This vulnerability occurs when a system processes both trusted and untrusted data together, but fails to separate them. The application…

CWE-351 Sibling

Insufficient Type Distinction

This vulnerability occurs when an application fails to properly differentiate between different types of data or objects, leading to…

CWE-352 Sibling

Cross-Site Request Forgery (CSRF)

Cross-Site Request Forgery (CSRF) happens when a web application cannot reliably tell if a user actually intended to submit a request,…

CWE-353 Sibling

Missing Support for Integrity Check

This vulnerability occurs when a system uses a communication protocol that lacks built-in integrity verification, such as a checksum or…

CWE-354 Sibling

Improper Validation of Integrity Check Value

This vulnerability occurs when software fails to properly check the integrity of data by validating its checksum or hash value. Without…

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