CWE-248 Base Draft

Uncaught Exception

This vulnerability occurs when a function throws an error or exception, but the calling code does not have a proper handler to catch and manage it.

Definition

What is CWE-248?

This vulnerability occurs when a function throws an error or exception, but the calling code does not have a proper handler to catch and manage it.

Uncaught exceptions break the normal flow of your application. Instead of gracefully handling an unexpected condition—like a failed network request, invalid input, or missing file—the program will typically terminate abruptly. This leads to a poor user experience, interrupted operations, and makes debugging more difficult, as the root cause may be obscured by a generic crash. Beyond causing crashes, unhandled exceptions can leak sensitive internal details about your application's structure, such as stack traces, file paths, or even partial data. Attackers can use this information to map your system and plan further exploits. To prevent this, developers should implement strategic try-catch blocks around risky operations and define clear fallback behaviors or user-friendly error messages.

Auswirkungen in der Praxis

Real-world CVEs caused by CWE-248

CVE-2023-41151

SDK for OPC Unified Architecture (OPC UA) server has uncaught exception when a socket is blocked for writing but the server tries to send an error
CVE-2023-21087

Java code in a smartphone OS can encounter a "boot loop" due to an uncaught exception

Wie Angreifer es ausnutzen

Angreiferpfad Schritt für Schritt

1
The following example attempts to resolve a hostname.
2
A DNS lookup failure will cause the Servlet to throw an exception.
3
The _alloca() function allocates memory on the stack. If an allocation request is too large for the available stack space, _alloca() throws an exception. If the exception is not caught, the program will crash, potentially enabling a denial of service attack. _alloca() has been deprecated as of Microsoft Visual Studio 2005(R). It has been replaced with the more secure _alloca_s().
4
EnterCriticalSection() can raise an exception, potentially causing the program to crash. Under operating systems prior to Windows 2000, the EnterCriticalSection() function can raise an exception in low memory situations. If the exception is not caught, the program will crash, potentially enabling a denial of service attack.

Verwundbares Codebeispiel

Vulnerable Java

The following example attempts to resolve a hostname.

Verwundbar Java

protected void doPost (HttpServletRequest req, HttpServletResponse res) throws IOException {
  	String ip = req.getRemoteAddr();
  	InetAddress addr = InetAddress.getByName(ip);
  	...
  	out.println("hello " + addr.getHostName());
  }

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-248

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.

Erkennungssignale

How to detect CWE-248

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-248 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-248?

This vulnerability occurs when a function throws an error or exception, but the calling code does not have a proper handler to catch and manage it.

Wie gravierend ist CWE-248?

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-248 betroffen?

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

Wie kann ich CWE-248 verhindern?

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.

Wie erkennt und behebt Plexicus CWE-248?

Die SAST-Engine von Plexicus erkennt die Datenfluss-Signatur von CWE-248 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-248?

MITRE veröffentlicht die kanonische Definition unter https://cwe.mitre.org/data/definitions/248.html. Für ergänzende Hinweise kannst du auch die OWASP- und NIST-Dokumentation heranziehen.

Verwandte Schwachstellen

Weaknesses related to CWE-248

CWE-705 Parent

Incorrect Control Flow Scoping

This vulnerability occurs when a program fails to return execution to the correct point in the code after finishing a specific operation…

CWE-382 Sibling

J2EE Bad Practices: Use of System.exit()

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CWE-395 Sibling

Use of NullPointerException Catch to Detect NULL Pointer Dereference

Using a try-catch block for NullPointerException as a substitute for proper null checks is an anti-pattern. This approach masks the root…

CWE-396 Sibling

Declaration of Catch for Generic Exception

This weakness occurs when code catches a generic exception type like 'Exception' or 'Throwable', which can hide specific errors and create…

CWE-397 Sibling

Declaration of Throws for Generic Exception

This vulnerability occurs when a method is declared to throw an overly broad exception type, such as a generic 'Exception' or 'Throwable'.…

CWE-455 Sibling

Non-exit on Failed Initialization

This vulnerability occurs when software continues to run as normal after encountering a critical security failure during its startup…

CWE-584 Sibling

Return Inside Finally Block

This vulnerability occurs when a function places a return statement inside a finally block. This dangerous pattern silently discards any…

CWE-698 Sibling

Execution After Redirect (EAR)

Execution After Redirect (EAR) occurs when a web application sends a redirect response to a user's browser but continues to run…

CWE-600 Child