VNX-124 – Buffer Underwrite ('Buffer Underflow')

Overview

VNX-124 maps to CWE-124: Buffer Underwrite (‘Buffer Underflow’). Detects source patterns associated with CWE-124 (Buffer Underwrite (‘Buffer Underflow’)). Each finding should be manually reviewed for exploitability in context.

Severity: High | CWE: CWE-124 | Languages: c, cpp

Why This Matters

This weakness class (Buffer Underwrite (‘Buffer Underflow’)) creates a concrete exploit surface: the rule searches for the concrete source-level patterns most commonly associated with CWE-124 and surfaces them for review. Each finding should be evaluated in context — the rule catches the pattern, not the context.

What Gets Flagged

// FLAGGED: contains 'memset(' pattern
memset(

// FLAGGED: contains '[-1]' pattern
[-1]

Remediation

  1. Review each flagged line and determine whether the pattern represents a real instance of CWE-124 or a false positive.
  2. Replace the flagged construct with a documented safe alternative appropriate to your language and framework.
  3. For confirmed false positives, add a # vulnetix-ignore: VNX-124 comment on the line.
  4. Ensure equivalent test coverage exists to prevent regression.

References