CWE-468 Base Incomplete Medium likelihood

Incorrect Pointer Scaling

This vulnerability occurs when a programmer incorrectly accounts for pointer arithmetic in C or C++, causing the program to access unintended memory locations. The core issue is forgetting that…

Definition

What is CWE-468?

This vulnerability occurs when a programmer incorrectly accounts for pointer arithmetic in C or C++, causing the program to access unintended memory locations. The core issue is forgetting that adding an integer to a pointer automatically scales that integer by the size of the data type it points to.
In C and C++, pointer arithmetic is not byte-based by default. When you add an integer `n` to a pointer, the compiler implicitly multiplies `n` by the `sizeof` the pointed-to type to get the correct byte offset. A common mistake is writing code that assumes a simple, unscaled addition, which leads to calculating an address far beyond or short of the intended target. This often happens when treating a pointer as a generic byte pointer (`void*` or `char*`) in some places but as a typed pointer (like `int*`) in others without proper casting. To prevent this, always be explicit about pointer types and scaling. When performing manual memory navigation, consistently use `char*` for byte-wise arithmetic or carefully cast pointers, ensuring you understand the compiler's implicit multiplications. Using container classes, iterators, or modern C++ smart pointers can often eliminate the need for raw pointer arithmetic altogether, sidestepping this entire class of errors.
Real-world impact

Real-world CVEs caused by CWE-468

No public CVE references are linked to this CWE in MITRE's catalog yet.

How attackers exploit it

Step-by-step attacker path

  1. 1

    Identify a code path that handles untrusted input without validation.

  2. 2

    Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.

  3. 3

    Deliver the payload through a normal request and observe the application's reaction.

  4. 4

    Iterate until the response leaks data, executes attacker code, or escalates privileges.

Vulnerable code example

Vulnerable C

This example attempts to calculate the position of the second byte of a pointer.

Vulnerable C 
int *p = x;
  char * second_char = (char *)(p + 1);
Secure code example

Secure pseudo

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-468

  • Architecture and Design Use a platform with high-level memory abstractions.
  • Implementation Always use array indexing instead of direct pointer manipulation.
  • Architecture and Design Use technologies for preventing buffer overflows.
Detection signals

How to detect CWE-468

SAST High

Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.

DAST Moderate

Run dynamic application security testing against the live endpoint.

Runtime Moderate

Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.

Code review Moderate

Code review: flag any new code that handles input from this surface without using the validated framework helpers.

Plexicus auto-fix

Plexicus auto-detects CWE-468 and opens a fix PR in under 60 seconds.

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Frequently asked questions

Frequently asked questions

What is CWE-468?

This vulnerability occurs when a programmer incorrectly accounts for pointer arithmetic in C or C++, causing the program to access unintended memory locations. The core issue is forgetting that adding an integer to a pointer automatically scales that integer by the size of the data type it points to.

How serious is CWE-468?

MITRE rates the likelihood of exploit as Medium — exploitation is realistic but typically requires specific conditions.

What languages or platforms are affected by CWE-468?

MITRE lists the following affected platforms: C, C++.

How can I prevent CWE-468?

Use a platform with high-level memory abstractions. Always use array indexing instead of direct pointer manipulation.

How does Plexicus detect and fix CWE-468?

Plexicus's SAST engine matches the data-flow signature for CWE-468 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-468?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/468.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-468

CWE-682 Parent

Incorrect Calculation

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CWE-128 Sibling

Wrap-around Error

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CWE-131 Sibling

Incorrect Calculation of Buffer Size

This vulnerability occurs when a program miscalculates the amount of memory needed for a buffer, potentially leading to a buffer overflow…

CWE-1335 Sibling

Incorrect Bitwise Shift of Integer

This vulnerability occurs when a program attempts to shift an integer's bits by an invalid amount—either a negative number or a value…

CWE-1339 Sibling

Insufficient Precision or Accuracy of a Real Number

This vulnerability occurs when a program uses a data type or algorithm that cannot accurately represent or calculate the fractional part…

CWE-135 Sibling

Incorrect Calculation of Multi-Byte String Length

This vulnerability occurs when software incorrectly measures the length of strings containing multi-byte or wide characters, leading to…

CWE-190 Sibling

Integer Overflow or Wraparound

Integer overflow or wraparound occurs when a calculation produces a numeric result that exceeds the maximum value a variable can hold.…

CWE-191 Sibling

Integer Underflow (Wrap or Wraparound)

Integer underflow occurs when a subtraction operation results in a value smaller than the data type's minimum limit, causing the value to…

CWE-193 Sibling

Off-by-one Error

An off-by-one error occurs when a program incorrectly calculates a boundary, such as a loop counter or array index, by being one unit too…

Resources

Further reading

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