Claude-skill-registry detecting-double-free

Detects double free vulnerabilities by identifying attempts to free the same memory block twice. Use when analyzing memory management, cleanup paths, or investigating heap corruption issues.

install

source · Clone the upstream repo

git clone https://github.com/majiayu000/claude-skill-registry

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/majiayu000/claude-skill-registry "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/data/detecting-double-free" ~/.claude/skills/majiayu000-claude-skill-registry-detecting-double-free && rm -rf "$T"

manifest: skills/data/detecting-double-free/SKILL.md

Double Free Detection

Detection Workflow

Identify free operations: Find all free() and delete/delete[] calls, note the pointers being freed
Track pointer usage: Use
```
xrefs_to
```
to trace pointers and identify pointer aliases
Analyze control flow: Map all code paths to free(), check for multiple free() calls on same pointer
Assess exploitability: Can attacker trigger double free? Is there useful heap corruption?

Key Patterns

Direct double free: free() called twice on same pointer
Conditional double free: free() in multiple code paths
Indirect double free: freeing same memory through different pointers
Reference counting issues

Output Format

Report with: id, type, subtype, severity, confidence, location, freed pointer, first free, second free, double free path, exploitability, attack scenario, impact, mitigation.

Severity Guidelines

CRITICAL: Double free with code execution potential
HIGH: Double free causing heap corruption
MEDIUM: Double free causing crashes
LOW: Double free with limited impact