CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')

What is CWE-93?

CWE-93 is Improper Neutralization of CRLF Sequences ('CRLF Injection'). The flaw arises when The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs. The database currently holds 114 vulnerabilities mapped to CWE-93 and none of them are in the CISA Known Exploited Vulnerabilities catalog.

Analyzing data...

OWASP TOP 10:2025 RANK5 — A05:2025 — Injection
Related CVES (365 days)114
AbstractionBase
Likelihood of exploit-

Vulnerabilities mapped to CWE-93

114 vulnerabilities1040% increase year over year

No data

No vulnerability data in CISA KEV for CWE-93

Official definition

ByMitre CWE

The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.

Characteristics

Modes of introduction

  • Implementation: REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Common consequences

ImpactScopeExplanation
Modify Application DataIntegrity-

Risk mitigations

  1. ImplementationAvoid using CRLF as a special sequence.
  2. ImplementationAppropriately filter or quote CRLF sequences in user-controlled input.

Detection methods

MethodApproachEffectiveness
Automated Static AnalysisAutomated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)High

Representative vulnerabilities

Sources (2)

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