CHANGES.rst

Changes

6.0.0 (NEXT)

Breaking Changes

• Pickle deserialization is now restricted to safe built-in types only. This mitigates CVE-2025-69872, which allowed arbitrary code execution when an attacker with write access to the cache directory injected a crafted pickle payload.

  The following types are permitted during deserialization:

  • Python builtins: int, float, str, bytes, bytearray, list, dict, tuple, set, frozenset, complex, range, slice, object, bool, None
  • collections: OrderedDict, defaultdict, deque
  • datetime: date, datetime, time, timedelta, timezone
  • decimal.Decimal
  • fractions.Fraction
  • uuid.UUID

  All other types will raise UnpicklingError on read.

• There is no opt-out mechanism. Users who need to cache custom types have two migration paths:

  1. Use JSONDisk for JSON-serializable data:

     cache = Cache('/tmp/my-cache', disk=JSONDisk)
     

  2. Subclass Disk and override get() and fetch() with a custom serialization strategy appropriate for your data.

New Features

• Added SafeUnpickler class for restricted pickle deserialization.
• Added UnpicklingError exception raised when a disallowed type is encountered during deserialization.

Internal

• SAFE_PICKLE_CLASSES uses frozenset values to prevent runtime modification.

5.6.3 (2023-08-31)

• Previous release (see git history for details).