CWE-155: Improper Neutralization of Wildcards or Matching Symbols

CWE-155: Improper Neutralization of Wildcards or Matching Symbols is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as wildcards or matching symbols when they are sent to a downstream component. As data is parsed, an injected element may cause the process to take unexpected actions.

If exploited, CWE-155 (Improper Neutralization of Wildcards or Matching Symbols) it can compromise Integrity, leading to outcomes such as Unexpected State.

Recommended mitigations for CWE-155 include: Developers should anticipate that wildcard or matching elements will be injected/removed/manipulated 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-155 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-155, including CVE-2002-0433, CVE-2002-1010, CVE-2001-0334 and CVE-2004-1962. 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-155 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.