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.
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.
// 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
// 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
CWE-685
Don't catalog this weakness. Prove it's reachable.
Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.
Häufig gestellte Fragen Was ist CWE-685?
Wie gravierend ist CWE-685?
Welche Sprachen oder Plattformen sind von CWE-685 betroffen?
Wie kann ich CWE-685 verhindern?
Wie erkennt und behebt Plexicus CWE-685?
Wo erfahre ich mehr über CWE-685?
Frequently asked questions
Was ist 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.
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
Further reading
Bereit, das Wesentliche zu validieren?
Bereit zu validieren, was zählt.
Plexicus ist Proof-Driven AppSec: validierte Funde, kontextuelles Verständnis und geprüfte Remediation — in Evidenz verankert, mit Ihnen gescoped.