CWE-130 Base Incomplete

Improper Handling of Length Parameter Inconsistency

This vulnerability occurs when a program reads a structured data packet or message but fails to properly validate that the declared length field matches the actual amount of data provided.

Definition

What is CWE-130?

This vulnerability occurs when a program reads a structured data packet or message but fails to properly validate that the declared length field matches the actual amount of data provided.
Attackers exploit this flaw by deliberately sending data where the stated length is incorrect—either longer or shorter than the real payload. This inconsistency tricks the application's parsing logic, often leading to catastrophic security failures like buffer overflows, memory corruption, or the processing of garbage data as if it were legitimate instructions. In practice, an attacker might use a manipulated length field to inject massive amounts of data beyond allocated buffers or to carefully craft input that alters critical application state. The core defense is for developers to always independently calculate or strictly verify data lengths during parsing, never trusting the user-supplied length parameter alone before processing the associated data block.
Auswirkungen in der Praxis

Real-world CVEs caused by CWE-130

  • CVE-2014-0160

    Chain: "Heartbleed" bug receives an inconsistent length parameter (CWE-130) enabling an out-of-bounds read (CWE-126), returning memory that could include private cryptographic keys and other sensitive data.

  • CVE-2009-2299

    Web application firewall consumes excessive memory when an HTTP request contains a large Content-Length value but no POST data.

  • CVE-2001-0825

    Buffer overflow in internal string handling routine allows remote attackers to execute arbitrary commands via a length argument of zero or less, which disables the length check.

  • CVE-2001-1186

    Web server allows remote attackers to cause a denial of service via an HTTP request with a content-length value that is larger than the size of the request, which prevents server from timing out the connection.

  • CVE-2001-0191

    Service does not properly check the specified length of a cookie, which allows remote attackers to execute arbitrary commands via a buffer overflow, or brute force authentication by using a short cookie length.

  • CVE-2003-0429

    Traffic analyzer allows remote attackers to cause a denial of service and possibly execute arbitrary code via invalid IPv4 or IPv6 prefix lengths, possibly triggering a buffer overflow.

  • CVE-2000-0655

    Chat client allows remote attackers to cause a denial of service or execute arbitrary commands via a JPEG image containing a comment with an illegal field length of 1.

  • CVE-2004-0492

    Server allows remote attackers to cause a denial of service and possibly execute arbitrary code via a negative Content-Length HTTP header field causing a heap-based buffer overflow.

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 C

In the following C/C++ example the method processMessageFromSocket() will get a message from a socket, placed into a buffer, and will parse the contents of the buffer into a structure that contains the message length and the message body. A for loop is used to copy the message body into a local character string which will be passed to another method for processing.

Verwundbar C 
int processMessageFromSocket(int socket) {
  		int success;
  		char buffer[BUFFER_SIZE];
  		char message[MESSAGE_SIZE];
```
// get message from socket and store into buffer* 
  		
  		
  		 *//Ignoring possibliity that buffer > BUFFER_SIZE* 
  		if (getMessage(socket, buffer, BUFFER_SIZE) > 0) {
  		```
```
// place contents of the buffer into message structure* 
  				ExMessage *msg = recastBuffer(buffer);
  				
  				
  				 *// copy message body into string for processing* 
  				int index;
  				for (index = 0; index < msg->msgLength; index++) {
  				```
  					message[index] = msg->msgBody[index];
  				}
  				message[index] = '\0';
```
// process message* 
  				success = processMessage(message);}
  		return success;}
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-130

  • Implementation When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data.
  • Implementation Do not let the user control the size of the buffer.
  • Implementation Validate that the length of the user-supplied data is consistent with the buffer size.
Erkennungssignale

How to detect CWE-130

SAST High

Führe statische Analyse (SAST) auf der Codebasis aus und suche im Datenfluss nach dem unsicheren Muster.

DAST Moderate

Führe dynamische Application-Security-Tests gegen den Live-Endpoint aus.

Runtime Moderate

Beobachte Runtime-Logs auf ungewöhnliche Exception-Traces, fehlerhafte Eingaben oder Versuche, Autorisierung zu umgehen.

Code review Moderate

Code Review: Markiere jeden neuen Code, der Eingaben von dieser Oberfläche ohne validierte Framework-Helper verarbeitet.

Plexicus Auto-Fix

Plexicus erkennt CWE-130 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-130?

This vulnerability occurs when a program reads a structured data packet or message but fails to properly validate that the declared length field matches the actual amount of data provided.

Wie gravierend ist CWE-130?

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-130 betroffen?

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

Wie kann ich CWE-130 verhindern?

When processing structured incoming data containing a size field followed by raw data, ensure that you identify and resolve any inconsistencies between the size field and the actual size of the data. Do not let the user control the size of the buffer.

Wie erkennt und behebt Plexicus CWE-130?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-130 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-130?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/130.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-130

CWE-240 Parent

Improper Handling of Inconsistent Structural Elements

This vulnerability occurs when a system fails to properly manage situations where related data structures or elements should match but are…

CWE-805 Kann vorausgehen

Buffer Access with Incorrect Length Value

This vulnerability occurs when software reads from or writes to a buffer using a loop or sequential operation, but mistakenly calculates…

Ressourcen

Further reading

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