HTTP Response Splitting
High · Injection
OWASP Top 10:2025 (current)
Not directly mapped to a Top 10:2025 category — see CWE / CVE below.
CWE
CWE-113
CVE / class examples
- Search NVD/CVE for product-specific instances of this CWE
All refs
CWE-113
Definition
CRLF in headers splits response into two.
Root cause
Unsanitized CRLF in Location/Set-Cookie headers.
Affected components
- Components in the “Injection” class
- Application / API handlers
- Supporting libraries
Impact
XSS, cache poisoning, session fixation.
Severity
High · CVSS 7.5
Safe lab reproduction
CRLF injection labs
Detection methodology
Header injection tests.
Evidence examples
- Lab reproduction notes: CRLF injection labs
- Request/response excerpts (redacted)
- Detection signal: Header injection tests
Remediation
Strip CRLF; use framework header APIs.
Secure coding examples
Never concatenate user input into headers.
Related CYNARKS lessons & labs
Tools: burp
Practise related skills in Labs or deepen on Academy library.