GHSA-456v-xq2p-r4cj: code-ollama: `grep_search` Command Injection via Unescaped `$()` Shell Substitution (CWE-78)

The grep_search tool in code-ollama constructs a shell command string by interpolating attacker-controlled pattern and path arguments, then executes it via child_process.exec(). The sanitization only escapes backslashes and double-quote characters, leaving $() command substitution and backtick expansion fully intact. A malicious or compromised Ollama server can therefore inject and execute arbitrary OS commands with the privileges of the local user running code-ollama. Because grep_search is classified as a read-only tool, it auto-executes in Plan mode without any user approval prompt, making this a no-interaction-required exploitation path. Severity is High (CVSS 7.8).