Vulnerable code sample

import os
import json
from abc import ABC, abstractmethod
from typing import Any, Optional
from pathlib import Path

# The following code is a self-contained representation of the vulnerable components
# from the 'anthropic' Python SDK version 0.86.0, related to CVE-2024-34450.
# The vulnerability exists in the `set` method of the `LocalFileMemory` class.

# --- Components from src/anthropic/beta/tools/memory/_serializer.py ---

class Serializer(ABC):
    @abstractmethod
    def dumps(self, obj: Any) -> str:
        ...

    @abstractmethod
    def loads(self, raw: str) -> Any:
        ...

class _JSONSerializer(Serializer):
    def dumps(self, obj: Any) -> str:
        return json.dumps(obj)

    def loads(self, raw: str) -> Any:
        return json.loads(raw)

_default_serializer: Optional[Serializer] = None

def default_serializer() -> Serializer:
    global _default_serializer
    if _default_serializer is None:
        _default_serializer = _JSONSerializer()
    return _default_serializer

# --- Components from src/anthropic/beta/tools/memory/_memory.py ---

class Memory(ABC):
    @abstractmethod
    def get(self, *, key: str) -> Any:
        ...

    @abstractmethod
    def set(self, *, key: str, value: Any) -> None:
        ...

    @abstractmethod
    def delete(self, *, key: str) -> None:
        ...

# --- Vulnerable code from src/anthropic/beta/tools/memory/file.py (version 0.86.0) ---

class LocalFileMemory(Memory):
    def __init__(
        self,
        *,
        persist_to: Path,
        serializer: Serializer = default_serializer(),
        # utf-8 is the default encoding for Path.read/write_text()
        encoding: str = "utf-8",
    ) -> None:
        self._persist_to = persist_to
        self._serializer = serializer
        self._encoding = encoding

    def _get_memory_path(self, key: str) -> Path:
        path = self._persist_to.joinpath(key)
        # ensure the parent directory exists
        path.parent.mkdir(exist_ok=True, parents=True)
        return path

    def get(self, *, key: str) -> Any:
        path = self._get_memory_path(key)
        if not path.exists():
            return None

        return self._serializer.loads(path.read_text(encoding=self._encoding))

    def set(self, *, key: str, value: Any) -> None:
        path = self._get_memory_path(key)
        # VULNERABLE LINE:
        # path.write_text() creates files using default permissions (e.g., 0o666)
        # before the system's umask is applied. In environments with a permissive
        # umask like 0o000 (common in Docker), this results in world-readable and
        # world-writable files.
        path.write_text(self._serializer.dumps(value), encoding=self._encoding)

    def delete(self, *, key: str) -> None:
        path = self._get_memory_path(key)
        if path.exists():
            os.remove(path)