Security: Unescaped commit hash in pull_upstream cherry-pick (CWE-78) #180

Summary

The pull_upstream tool interpolates the commit parameter directly into a git cherry-pick command with no escaping. While the policy engine's validate.git_hash rule validates commit format at the policy layer, defense-in-depth requires validation at execution time. A policy bypass or misconfigured rule would expose this injection point.

Vulnerable Code

if (commit) {
  await run(`git cherry-pick ${commit}`);
  appliedSummary = `Cherry-picked ${commit}`;
}

Recommendation

Validate at execution time with /^[a-f0-9]{7,40}$/ and use escapeShellArg():

if (!/^[a-f0-9]{7,40}$/.test(commit)) {
  return `Blocked: invalid commit hash "${commit}"`;
}
await run(`git cherry-pick -- ${escapeShellArg(commit)}`);

Severity: HIGH
CWE: CWE-78 (OS Command Injection)
Location: src/agent/tools.ts — line 511