CWE-1074 Base Incomplete

Class with Excessively Deep Inheritance

This weakness occurs when a class inherits from an excessive number of parent classes, creating a deep and complex inheritance hierarchy.

Definition

What is CWE-1074?

This weakness occurs when a class inherits from an excessive number of parent classes, creating a deep and complex inheritance hierarchy.
Excessively deep inheritance chains make code significantly harder to understand, test, and maintain. This complexity indirectly harms security by obscuring logic flow, increasing the time needed to find bugs, and raising the risk of introducing new vulnerabilities during modifications. The deeper the hierarchy, the more difficult it becomes to trace method execution and state changes. While the specific threshold for "too deep" can vary by project, the CISQ (Consortium for IT Software Quality) standard recommends a maximum inheritance depth of seven parent classes. Adhering to this guideline helps maintain code clarity, reduces tight coupling, and makes security reviews more effective by keeping the class structure manageable.
Real-world impact

Real-world CVEs caused by CWE-1074

No public CVE references are linked to this CWE in MITRE's catalog yet.

How attackers exploit it

Step-by-step attacker path

  1. 1

    Identify a code path that handles untrusted input without validation.

  2. 2

    Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.

  3. 3

    Deliver the payload through a normal request and observe the application's reaction.

  4. 4

    Iterate until the response leaks data, executes attacker code, or escalates privileges.

Vulnerable code example

Vulnerable pseudo

MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.

Vulnerable pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
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-1074

  • 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-1074

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-1074 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-1074?

This weakness occurs when a class inherits from an excessive number of parent classes, creating a deep and complex inheritance hierarchy.

How serious is CWE-1074?

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-1074?

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

How can I prevent CWE-1074?

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-1074?

Plexicus's SAST engine matches the data-flow signature for CWE-1074 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-1074?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/1074.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-1074

CWE-1093 Parent

Excessively Complex Data Representation

This weakness occurs when software uses an overly complicated internal model to represent its data or the relationships between data…

CWE-1043 Sibling

Data Element Aggregating an Excessively Large Number of Non-Primitive Elements

This weakness occurs when a data structure, like a class or object, contains too many complex sub-elements (e.g., other objects or…

CWE-1055 Sibling

Multiple Inheritance from Concrete Classes

This weakness occurs when a single class inherits functionality and state from more than one concrete (fully implemented) parent class.

CWE-1086 Sibling

Class with Excessive Number of Child Classes

This weakness occurs when a parent class has an excessive number of child classes that inherit from it, creating a deep and overly complex…

Resources

Further reading

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