CWE-153: Improper Neutralization of Substitution Characters
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as substitution characters when they are sent to a downstream component.
View on MITRETechnical Details
- Structure
- Simple
Applicable To
Security Consequences
Scope
Impact
Mitigation Strategies
Phase
Description
Developers should anticipate that substitution characters 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.
Detection Methods
No detection method information available for this CWE.
Code Examples & CVEs
Observed CVE Examples (1)
Server trusts client to expand macros, allows macro characters to be expanded to trigger resultant information exposure.
View DetailsCWE Relationships
Frequently Asked Questions
What is CWE-153: Improper Neutralization of Substitution Characters?+
CWE-153: Improper Neutralization of Substitution Characters 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 substitution characters when they are sent to a downstream component.
What are the security consequences of Improper Neutralization of Substitution Characters?+
If exploited, CWE-153 (Improper Neutralization of Substitution Characters) it can compromise Integrity, leading to outcomes such as Unexpected State.
How do you prevent or mitigate Improper Neutralization of Substitution Characters?+
Recommended mitigations for CWE-153 include: Developers should anticipate that substitution characters 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.
Which programming languages are affected by Improper Neutralization of Substitution Characters?+
CWE-153 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.
What are real-world examples of Improper Neutralization of Substitution Characters?+
MITRE documents real CVEs mapped to CWE-153, including CVE-2002-0770. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.
What is the difference between a CWE and a CVE?+
A CWE (Common Weakness Enumeration) like CWE-153 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.