The product receives input from an upstream component, but it does not handle or incorrectly handles when an expected special element is missing.
View on MITREDevelopers should anticipate that special elements will be removed in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
No detection method information available for this CWE.
HTTP GET without \r\n\r\n CRLF sequences causes product to wait indefinitely and prevents other users from accessing it
View DetailsCWE-166: Improper Handling of Missing Special Element is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product receives input from an upstream component, but it does not handle or incorrectly handles when an expected special element is missing.
If exploited, CWE-166 (Improper Handling of Missing Special Element) it can compromise Availability, leading to outcomes such as DoS: Crash, Exit, or Restart.
Recommended mitigations for CWE-166 include: Developers should anticipate that special elements will be removed in the input vectors of their product. Use an appropriate combination of denylists and allowlists to ensure only valid, expected and appropriate input is processed by the system.
CWE-166 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-166, including CVE-2002-1362, CVE-2002-0729 and CVE-2002-1532. 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-166 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.