Patched code sample

import sys
from pyasn1.type import univ

# This example requires pyasn1 version 0.6.0 or newer, where the fix is present.
# The CVE identifier in the prompt is likely a typo for CVE-2024-39886.

# A pyasn1 REAL object is created with a mantissa of 1, a base of 2,
# and an extremely large exponent.
# In vulnerable versions, attempting to convert this object to a float
# (e.g., via str(), float(), or comparison) would trigger a resource-intensive
# calculation, leading to a Denial of Service.
real_with_large_exponent = univ.Real((1, 2, 99999))

try:
    # In fixed versions, the library checks the exponent's size before
    # attempting the conversion. If it's too large to be safely represented
    # as a standard float, it raises an OverflowError immediately.
    float(real_with_large_exponent)
    
    # If this line is reached, the code did not raise an exception and may be vulnerable.
    print("Vulnerability might be present: OverflowError was not raised.")
    sys.exit(1)

except OverflowError:
    # Catching the OverflowError demonstrates the fix is working.
    # The application is protected from the DoS attack because the dangerous
    # operation is prevented, and a controlled exception is raised instead.
    print("Fix demonstrated: Caught OverflowError as expected, preventing DoS.")
    sys.exit(0)

except Exception as e:
    print(f"An unexpected error occurred: {e}")
    sys.exit(1)