CWE-685 Variant Draft

Function Call With Incorrect Number of Arguments

This weakness occurs when a program calls a function, method, or subroutine but provides the wrong number of arguments—either too many or too few. This mismatch can cause the program to behave…

Definition

What is CWE-685?

This weakness occurs when a program calls a function, method, or subroutine but provides the wrong number of arguments—either too many or too few. This mismatch can cause the program to behave unpredictably, access incorrect memory, or crash, creating a security vulnerability.

When a function is called with an incorrect argument count, the underlying system mechanics break down. The calling code and the function have mismatched expectations about how data is arranged on the stack or in registers. This can lead to the function reading invalid values, interpreting data incorrectly (like treating a string as a pointer), or corrupting adjacent memory. The immediate result is often undefined behavior, which can manifest as crashes, data corruption, or unexpected program flow. From a security perspective, this flaw is a gateway for more severe exploits. An attacker might manipulate this mismatch to leak sensitive data from memory, bypass security checks, or execute arbitrary code. It's commonly seen in languages that don't enforce strict type checking at compile-time (like C or C++), in cases of incorrect function pointer usage, or when interfacing with external libraries. Developers must ensure function signatures are always correctly matched, especially when using dynamic linking or callback mechanisms.

Auswirkungen in der Praxis

Real-world CVEs caused by CWE-685

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

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

1
Identifiziere einen Codepfad, der nicht vertrauenswürdige Eingaben ohne Validierung verarbeitet.
2
Erzeuge eine Payload, die das unsichere Verhalten auslöst — Injection, Traversal, Overflow oder Logik-Missbrauch.
3
Liefere die Payload über einen normalen Request aus und beobachte die Reaktion der Anwendung.
4
Iteriere, bis die Antwort Daten preisgibt, Angreifer-Code ausführt oder Berechtigungen eskaliert.

Verwundbares Codebeispiel

Vulnerable pseudo

MITRE hat kein Codebeispiel für diese CWE veröffentlicht. Das untenstehende Muster ist illustrativ — kanonische Referenzen findest du unter Ressourcen.

Verwundbar pseudo

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

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-685

Testing Because this function call often produces incorrect behavior it will usually be detected during testing or normal operation of the product. During testing exercise all possible control paths will typically expose this weakness except in rare cases when the incorrect function call accidentally produces the correct results or if the provided argument type is very similar to the expected argument type.

Erkennungssignale

How to detect CWE-685

Other

While this weakness might be caught by the compiler in some languages, it can occur more frequently in cases in which the called function accepts variable numbers of arguments, such as format strings in C. It also can occur in languages or environments that do not require that functions always be called with the correct number of arguments, such as Perl.

Plexicus Auto-Fix

Plexicus erkennt CWE-685 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-685?

Wie gravierend ist CWE-685?

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-685 betroffen?

MITRE lists the following affected platforms: C, Perl.

Wie kann ich CWE-685 verhindern?

Because this function call often produces incorrect behavior it will usually be detected during testing or normal operation of the product. During testing exercise all possible control paths will typically expose this weakness except in rare cases when the incorrect function call accidentally produces the correct results or if the provided argument type is very similar to the expected argument type.

Wie erkennt und behebt Plexicus CWE-685?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-685 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-685?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/685.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-685

CWE-628 Parent

Function Call with Incorrectly Specified Arguments

This weakness occurs when a function is called with arguments that are incorrectly specified, causing the function to behave in an…

CWE-683 Sibling

Function Call With Incorrect Order of Arguments

This vulnerability occurs when a program calls a function but supplies the arguments in the wrong order, which can cause unexpected…

CWE-686 Sibling

Function Call With Incorrect Argument Type

This vulnerability occurs when a program calls a function or method but passes an argument of the wrong data type, which can cause…

CWE-687 Sibling

Function Call With Incorrectly Specified Argument Value

This vulnerability occurs when a function is called with an argument that holds an incorrect or unexpected value, leading to unintended…

CWE-688 Sibling

Function Call With Incorrect Variable or Reference as Argument

This vulnerability occurs when a function is called with the wrong variable or reference passed as an argument. This simple coding mistake…

Ressourcen

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