What is CWE-150: Improper Neutralization of Escape, Meta, or Control Sequences?+
CWE-150: Improper Neutralization of Escape, Meta, or Control Sequences 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 escape, meta, or control character sequences when they are sent to a downstream component.
What are the security consequences of Improper Neutralization of Escape, Meta, or Control Sequences?+
If exploited, CWE-150 (Improper Neutralization of Escape, Meta, or Control Sequences) it can compromise Integrity, leading to outcomes such as Execute Unauthorized Code or Commands, Hide Activities and Unexpected State.
How do you prevent or mitigate Improper Neutralization of Escape, Meta, or Control Sequences?+
Recommended mitigations for CWE-150 include: Developers should anticipate that escape, meta and control characters/sequences 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. When using output from an LLM, neutralize or strip escape codes before redirecting output to the terminal or other rendering engine that would process the codes. The neutralization could require that the character be printable and/or allowable whitespace, such as a carriage return or newline. Be deliberate about what to allow. When using an LLM: during tokenizer training, suppress escape codes from the tokenizer's vocabulary. Depending on context, this could be accomplished by removing the codes from input to the tokenizer, or removing the map from the string to its token ID. It is generally unlikely that this removal would adversely affect the quality or correctness of what is generated, e.g. advice requests for terminal settings to change colors.
Which programming languages are affected by Improper Neutralization of Escape, Meta, or Control Sequences?+
CWE-150 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 Escape, Meta, or Control Sequences?+
MITRE documents real CVEs mapped to CWE-150, including CVE-2024-27936, CVE-2002-0542, CVE-2000-0703, CVE-2002-0986 and CVE-2003-0020. 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-150 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.