CWE-588 Variant Incomplete

Attempt to Access Child of a Non-structure Pointer

This vulnerability occurs when code incorrectly treats a pointer to a basic data type (like an integer) as if it points to a structured object (like a 'struct' in C). The program then tries to…

Definition

What is CWE-588?

This vulnerability occurs when code incorrectly treats a pointer to a basic data type (like an integer) as if it points to a structured object (like a 'struct' in C). The program then tries to access a member field that doesn't exist at that memory location, which can cause crashes or corrupt adjacent data.
At its core, this issue is a type confusion error. The developer assumes a block of memory is organized as a specific structure with defined fields, but in reality, it holds a different, simpler type. When the code attempts to read or write to a supposed structure member, it calculates an offset into memory that is meaningless for the actual data stored there. This leads to accessing unintended memory locations, resulting in segmentation faults, unpredictable program behavior, or the silent corruption of other variables. To prevent this, always ensure type consistency when casting pointers. Use strict compiler warnings and static analysis tools to catch questionable casts. When working with raw memory buffers or generic pointers (like `void*`), implement explicit checks or use tagged unions to track the actual data type before performing any structure-like access. Defensive programming and clear code documentation about data layout are essential safeguards.
Real-world impact

Real-world CVEs caused by CWE-588

  • CVE-2021-3510

    JSON decoder accesses a C union using an invalid offset to an object

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

The following example demonstrates the weakness.

Vulnerable C 
struct foo
  {
  	int i;
  }
  ...
  int main(int argc, char **argv)
  {
  	*foo = (struct foo *)main;
  	foo->i = 2;
  	return foo->i;
  }
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-588

  • Requirements The choice could be made to use a language that is not susceptible to these issues.
  • Implementation Review of type casting operations can identify locations where incompatible types are cast.
Detection signals

How to detect CWE-588

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-588 and opens a fix PR in under 60 seconds.

Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.

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Frequently asked questions

Frequently asked questions

What is CWE-588?

This vulnerability occurs when code incorrectly treats a pointer to a basic data type (like an integer) as if it points to a structured object (like a 'struct' in C). The program then tries to access a member field that doesn't exist at that memory location, which can cause crashes or corrupt adjacent data.

How serious is CWE-588?

MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.

What languages or platforms are affected by CWE-588?

MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.

How can I prevent CWE-588?

The choice could be made to use a language that is not susceptible to these issues. Review of type casting operations can identify locations where incompatible types are cast.

How does Plexicus detect and fix CWE-588?

Plexicus's SAST engine matches the data-flow signature for CWE-588 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-588?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/588.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-588

CWE-704 Parent

Incorrect Type Conversion or Cast

This vulnerability occurs when software incorrectly changes data from one type to another, leading to unexpected behavior or security flaws.

CWE-1389 Sibling

Incorrect Parsing of Numbers with Different Radices

This vulnerability occurs when software processes numeric input expecting standard decimal numbers (base 10), but fails to handle inputs…

CWE-681 Sibling

Incorrect Conversion between Numeric Types

This vulnerability occurs when a program converts a value from one numeric type to another (like a 64-bit integer to a 32-bit integer) and…

CWE-843 Sibling

Access of Resource Using Incompatible Type ('Type Confusion')

Type confusion occurs when a program creates a resource—like a pointer, object, or variable—with one data type, but later incorrectly…

Resources

Further reading

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