CWE-496 Variant Incomplete

Public Data Assigned to Private Array-Typed Field

This vulnerability occurs when a developer stores sensitive data in a private array, but then assigns a publicly accessible reference to that same array. This effectively makes all the private…

Definition

What is CWE-496?

This vulnerability occurs when a developer stores sensitive data in a private array, but then assigns a publicly accessible reference to that same array. This effectively makes all the private array's contents available to unauthorized code, bypassing intended access controls.
When you declare an array field as `private`, you're telling the system that external code shouldn't directly access it. However, if you then assign a public variable or return value to point to that same private array, you've created a backdoor. Any code with access to the public reference can now read, modify, or delete the supposedly private data, completely undermining your encapsulation. To prevent this, never expose references to your private arrays. Instead, return copies (defensive copies) of the array data or use immutable collections. Always validate that your getter methods or public fields don't provide direct access to mutable private objects, as this is a common oversight that leads to serious data exposure.
Auswirkungen in der Praxis

Real-world CVEs caused by CWE-496

Bisher sind in MITREs Katalog keine öffentlichen CVE-Referenzen mit dieser CWE verknüpft.

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

  1. 1

    Identifiziere einen Codepfad, der nicht vertrauenswürdige Eingaben ohne Validierung verarbeitet.

  2. 2

    Erzeuge eine Payload, die das unsichere Verhalten auslöst — Injection, Traversal, Overflow oder Logik-Missbrauch.

  3. 3

    Liefere die Payload über einen normalen Request aus und beobachte die Reaktion der Anwendung.

  4. 4

    Iteriere, bis die Antwort Daten preisgibt, Angreifer-Code ausführt oder Berechtigungen eskaliert.

Verwundbares Codebeispiel

Vulnerable Java

In the example below, the setRoles() method assigns a publically-controllable array to a private field, thus allowing the caller to modify the private array directly by virtue of the fact that arrays in Java are mutable.

Verwundbar Java 
private String[] userRoles;
  public void setUserRoles(String[] userRoles) {
  	this.userRoles = userRoles;
  }
Sicheres Codebeispiel

Secure pseudo

Sicher 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.
Präventions-Checkliste

How to prevent CWE-496

  • Implementation Do not allow objects to modify private members of a class.
Erkennungssignale

How to detect CWE-496

Automated Static Analysis High

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Plexicus Auto-Fix

Plexicus erkennt CWE-496 automatisch und öffnet in unter 60 Sekunden einen Fix-PR.

Codex Remedium scannt jeden Commit, identifiziert genau diese Schwachstelle und liefert einen reviewer-ready Pull Request mit dem Patch. Keine Tickets. Keine Hand-offs.

Demo anfordern Plexicus kostenlos testen
Häufig gestellte Fragen

Frequently asked questions

Was ist CWE-496?

This vulnerability occurs when a developer stores sensitive data in a private array, but then assigns a publicly accessible reference to that same array. This effectively makes all the private array's contents available to unauthorized code, bypassing intended access controls.

Wie gravierend ist CWE-496?

MITRE hat für diese Schwachstelle keine Exploit-Wahrscheinlichkeit veröffentlicht. Behandle sie als mittlere Auswirkung, bis dein Threat Model anderes belegt.

Welche Sprachen oder Plattformen sind von CWE-496 betroffen?

MITRE lists the following affected platforms: C, C++, Java, C#.

Wie kann ich CWE-496 verhindern?

Do not allow objects to modify private members of a class.

Wie erkennt und behebt Plexicus CWE-496?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-496 bei jedem Commit. Bei einem Treffer öffnet unser Codex-Remedium-Agent einen Fix-PR mit korrigiertem Code, Tests und einer einzeiligen Zusammenfassung für den Reviewer.

Wo erfahre ich mehr über CWE-496?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/496.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-496

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

This vulnerability occurs when a system's normal operations unintentionally create new, exploitable resources that attackers can use to…

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…

Ressourcen

Further reading

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