CWE-1114 is source code whose whitespace is inconsistent across the codebase or does not follow the expected standard for the product. MITRE files it as a class level child of CWE-1078, inappropriate source code style or formatting.
MITRE marks the entry as a quality issue with no direct security implications and prohibits mapping vulnerabilities to it directly. Yet it lists one very famous bug as an observed example, and that example shows exactly why whitespace is a security matter.
How it happens
Developers mix tabs and spaces, use different indentation widths, or let an editor reformat only the lines they touched. In languages that use braces rather than indentation to define blocks, the compiler ignores whitespace entirely. A human does not.
The observed example is CVE-2014-1266. MITRE describes it as a chain: an incorrect goto in Apple's SSL product bypassed certificate validation, enabling an adversary in the middle attack. This is the bug widely known as goto fail. The MITRE record maps the chain to CWE-705, incorrect control flow scoping, and to CWE-56.
What an attacker gains
MITRE lists two consequences. The first is increased analytical complexity: a human auditor might indirectly trust that whitespace, especially indentation, reflects the actual control flow of the code, which could make it more difficult to find vulnerabilities. The second is reduced maintainability.
In other words, the attacker does not exploit the whitespace. The attacker benefits when a reviewer is misled by it. In the CVE above, the result was that certificate validation could be skipped.
How it looks in code
This is a simplified, illustrative sketch of the pattern, not the original source.
/* Vulnerable pattern: the second goto is NOT part of the if.
Indentation suggests otherwise. */
if ((err = check_a()) != 0)
goto fail;
goto fail; /* always runs */
if ((err = check_b()) != 0)
goto fail;
A reader sees two checks. The compiler sees one check followed by an unconditional jump, so the second check never runs and err may still be zero when control reaches the failure label.
The fix is to always use braces and let a formatter set the indentation.
/* Fixed: braces make the scope explicit */
if ((err = check_a()) != 0) {
goto fail;
}
if ((err = check_b()) != 0) {
goto fail;
}
How to find it
The record lists no detection methods. These checks catch most of the real risk:
- Run an automatic formatter in CI and fail the build if the code is not formatted.
- Enable compiler warnings for misleading indentation, where your compiler supports one.
- Use a linter rule that requires braces on every conditional.
- Flag unreachable code with static analysis, since a skipped check often leaves dead code behind.
How to fix it
The MITRE record lists no formal mitigations. The practices above are the usual answer. Pick one whitespace standard, write it down, and enforce it with tools rather than with reviewer attention. Require braces for every control statement, and review diffs with whitespace changes visible.
Quick check
Does whitespace affect how a C compiler behaves?
Not for scoping. Braces and statements decide that. The danger is that human reviewers rely on indentation, and it can disagree with the real control flow.
What is the cheapest control?
An automatic formatter that runs in CI, plus a rule that every if has braces.
