VNX-135 – Incorrect Calculation of Multi-Byte String Length

Overview

VNX-135 maps to CWE-135: Incorrect Calculation of Multi-Byte String Length. Detects source patterns associated with CWE-135 (Incorrect Calculation of Multi-Byte String Length). Each finding should be manually reviewed for exploitability in context.

Severity: Medium | CWE: CWE-135 | Languages: c, cpp

Why This Matters

This weakness class (Incorrect Calculation of Multi-Byte String Length) creates a concrete exploit surface: the rule searches for the concrete source-level patterns most commonly associated with CWE-135 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 'strlen(' pattern
strlen(

Remediation

  1. Review each flagged line and determine whether the pattern represents a real instance of CWE-135 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-135 comment on the line.
  4. Ensure equivalent test coverage exists to prevent regression.

References