This vulnerability occurs when an application accepts user input and fails to properly sanitize characters that can be interpreted as comment markers (like /*, */, //, #, or <!--) before passing that data to another system component. This allows an attacker to inject malicious comments that can break data processing, alter logic, or expose sensitive information.

How serious is CWE-151?

MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.

What languages or platforms are affected by CWE-151?

MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.

How can I prevent CWE-151?

Developers should anticipate that comments 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. Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or…

How does Plexicus detect and fix CWE-151?

Plexicus's SAST engine matches the data-flow signature for CWE-151 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.

Where can I learn more about CWE-151?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/151.html. You can also reference OWASP and NIST documentation for adjacent guidance.

CWE-151 Variant Draft

Improper Neutralization of Comment Delimiters

This vulnerability occurs when an application accepts user input and fails to properly sanitize characters that can be interpreted as comment markers (like /*, */, //, #, or <!--) before passing…

Definition

What is CWE-151?

This vulnerability occurs when an application accepts user input and fails to properly sanitize characters that can be interpreted as comment markers (like /*, */, //, #, or