Automated 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.)
CWE-483 Base Draft
Incorrect Block Delimitation
This vulnerability occurs when a developer fails to use explicit braces or delimiters to group multiple statements within a block, leading to unexpected program logic.
Definition
What is CWE-483?
This vulnerability occurs when a developer fails to use explicit braces or delimiters to group multiple statements within a block, leading to unexpected program logic.
In programming languages like JavaScript, Python, or Go, braces, indentation, or keywords are sometimes optional for single-statement blocks. However, when you intend for multiple statements to execute together—such as within an `if` condition or a loop—omitting the explicit block delimiter means only the first statement is controlled by that condition. Subsequent statements execute unconditionally, creating a critical logic error.
This error often manifests as a subtle bug where security-critical operations, like privilege checks or input validation, are bypassed. For example, an access control check might only guard a logging statement while allowing the actual data transaction to proceed without authorization. Always use explicit delimiters for multi-statement blocks to ensure your code's logic and security controls behave as intended.
Real-world impact
Real-world CVEs caused by CWE-483
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incorrect indentation of "goto" statement makes it more difficult to detect an incorrect goto (Apple's "goto fail")
How attackers exploit it
Step-by-step attacker path
- 1
In this example, the programmer has indented the statements to call Do_X() and Do_Y(), as if the intention is that these functions are only called when the condition is true. However, because there are no braces to signify the block, Do_Y() will always be executed, even if the condition is false.
- 2
This might not be what the programmer intended. When the condition is critical for security, such as in making a security decision or detecting a critical error, this may produce a vulnerability.
- 3
In this example, the programmer has indented the Do_Y() statement as if the intention is that the function should be associated with the preceding conditional and should only be called when the condition is true. However, because Do_X() was called on the same line as the conditional and there are no braces to signify the block, Do_Y() will always be executed, even if the condition is false.
- 4
This might not be what the programmer intended. When the condition is critical for security, such as in making a security decision or detecting a critical error, this may produce a vulnerability.
Vulnerable code example
Vulnerable C
In this example, the programmer has indented the statements to call Do_X() and Do_Y(), as if the intention is that these functions are only called when the condition is true. However, because there are no braces to signify the block, Do_Y() will always be executed, even if the condition is false.
if (condition==true)
Do_X();
Do_Y(); Secure code example
Secure pseudo
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
const safe = validateAndEscape(input);
return executeWithGuards(safe);
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist
How to prevent CWE-483
- Implementation Always use explicit block delimitation and use static-analysis technologies to enforce this practice.
Detection signals
How to detect CWE-483
CWE-483
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Frequently asked questions What is CWE-483?
How serious is CWE-483?
What languages or platforms are affected by CWE-483?
How can I prevent CWE-483?
How does Plexicus detect and fix CWE-483?
Where can I learn more about CWE-483?
Frequently asked questions
What is CWE-483?
This vulnerability occurs when a developer fails to use explicit braces or delimiters to group multiple statements within a block, leading to unexpected program logic.
How serious is CWE-483?
MITRE rates the likelihood of exploit as Low — exploitation is uncommon, but the weakness should still be fixed when discovered.
What languages or platforms are affected by CWE-483?
MITRE lists the following affected platforms: C, C++.
How can I prevent CWE-483?
Always use explicit block delimitation and use static-analysis technologies to enforce this practice.
How does Plexicus detect and fix CWE-483?
Plexicus's SAST engine matches the data-flow signature for CWE-483 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-483?
MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/483.html. You can also reference OWASP and NIST documentation for adjacent guidance.
Related weaknesses
Weaknesses related to CWE-483
CWE-670 Parent
Always-Incorrect Control Flow Implementation
This weakness occurs when a section of code is structured in a way that always executes incorrectly, regardless of input or conditions.…
CWE-480 Sibling
Use of Incorrect Operator
This vulnerability occurs when a developer mistakenly uses the wrong operator in their code, leading to unintended and potentially…
CWE-484 Sibling
Omitted Break Statement in Switch
This vulnerability occurs when a developer forgets to include a 'break' statement inside a switch-case block. Without it, the code…
CWE-617 Sibling
Reachable Assertion
A reachable assertion occurs when an attacker can trigger an assert() statement or similar debugging check, causing the application to…
CWE-698 Sibling
Execution After Redirect (EAR)
Execution After Redirect (EAR) occurs when a web application sends a redirect response to a user's browser but continues to run…
CWE-783 Sibling
Operator Precedence Logic Error
This vulnerability occurs when a developer writes a conditional expression where the intended logic is broken due to misunderstanding or…
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