The product does not handle or incorrectly handles an exceptional condition.
View on MITRENo mitigation information available for this CWE.
No detection method information available for this CWE.
The following example attempts to resolve a hostname.
A DNS lookup failure will cause the Servlet to throw an exception.
protected void doPost (HttpServletRequest req, HttpServletResponse res) throws IOException {String ip = req.getRemoteAddr();InetAddress addr = InetAddress.getByName(ip);...out.println("hello " + addr.getHostName());}The following example attempts to allocate memory for a character. After the call to malloc, an if statement is used to check whether the malloc function failed.
The conditional successfully detects a NULL return value from malloc indicating a failure, however it does not do anything to handle the problem. Unhandled errors may have unexpected results and may cause the program to crash or terminate.
foo=malloc(sizeof(char)); //the next line checks to see if malloc failedif (foo==NULL) {//We do nothing so we just ignore the error.}The following example attempts to allocate memory for a character. After the call to malloc, an if statement is used to check whether the malloc function failed.
The conditional successfully detects a NULL return value from malloc indicating a failure, however it does not do anything to handle the problem. Unhandled errors may have unexpected results and may cause the program to crash or terminate.
foo=malloc(sizeof(char)); //the next line checks to see if malloc failedif (foo==NULL) {printf("Malloc failed to allocate memory resources");return -1;}The following code mistakenly catches a NullPointerException.
try { mysteryMethod(); } catch (NullPointerException npe) { }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
View DetailsChain: JavaScript-based cryptocurrency library can fall back to the insecure Math.random() function instead of reporting a failure (CWE-392), thus reducing the entropy (CWE-332) and leading to generation of non-unique cryptographic keys for Bitcoin wallets (CWE-1391)
View Detailsvirtual interrupt controller in a virtualization product allows crash of host by writing a certain invalid value to a register, which triggers a fatal error instead of returning an error code
View DetailsChain: OS kernel does not properly handle a failure of a function call (CWE-755), leading to an unlock of a resource that was not locked (CWE-832), with resultant crash.
View DetailsAdditional facts reviewed against primary or authoritative security sources.
Documented detection approaches include Automated Static Analysis; recorded impacts include Other; observed examples include CVE-2023-41151, CVE-2021-3011, and CVE-2008-4302. Use these source-defined anchors to turn CWE-755 into implementation, review, and verification checks for the affected component.
CWE-755: Improper Handling of Exceptional Conditions — MITRE CWEUse NIST SSDF practices to make prevention of CWE-755, Improper Handling of Exceptional Conditions, an explicit development outcome. Translate the CWE definition into security requirements and design constraints, choose safer implementation patterns and toolchain checks, and define acceptance evidence before release. Feed every confirmed occurrence back into the requirements, design review, and coding rules so the same root cause is removed across the product rather than patched in one location.
NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and TechnologyUse CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-755, Improper Handling of Exceptional Conditions, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.
Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security AgencyApply MITRE's full root-cause mapping guidance when using CWE-755, Improper Handling of Exceptional Conditions. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.
CVE to CWE Root Cause Mapping Guidance — MITRE CWEApply MITRE's root-cause mapping quick tips to CWE-755, Improper Handling of Exceptional Conditions. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.
CVE to CWE Root Cause Mapping Quick Tips — MITRE CWECWE-755: Improper Handling of Exceptional Conditions is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product does not handle or incorrectly handles an exceptional condition.
If exploited, CWE-755 (Improper Handling of Exceptional Conditions) it can compromise Other, leading to outcomes such as Other.
CWE-755 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.
MITRE documents real CVEs mapped to CWE-755, including CVE-2023-41151, [REF-1374], CVE-2021-3011 and CVE-2008-4302. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.
A CWE (Common Weakness Enumeration) like CWE-755 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.