Tested fixes for CWE-1236 in Express, Flask, Spring Boot, ASP.NET Core, Django and Rails: the vulnerable code, the fix, a plausible fix that still fails, and the regression tests.
The description above is MITRE’s definition of CWE-1236 in CWE 4.20, a base-level weakness.
Common consequences MITRE lists
- Confidentiality: Read Application Data; Execute Unauthorized Code or Commands
Guides on this site
Prevent CRLF header injection, log forging and CSV formula injection
Carriage return and line feed separate HTTP header fields, log records and CSV rows, and a leading = turns a spreadsheet cell into a formula. Let the framework write headers, log structured JSON, and neutralize formula triggers in exports.
Abuse case library: tests and controls by feature
Recurring abuse cases for sign-up and login, password reset, MFA enrolment, invites, file upload, payments and coupons, webhooks, search, export, admin and AI chat or agents: the attacker goal, preconditions, a concrete test and the control, each linked to CWE and CAPEC.
References
This page is generated from MITRE’s CWE 4.20 catalogue (released 30 April 2026) and lists every guide, fix card and lab here that cites CWE-1236.
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