A vulnerability in the pyasn1 library's univ.Real type allows an attacker to cause excessive CPU and memory consumption when converting decoded REAL values with large exponents to Python floats. This can lead to denial of service in applications that decode untrusted ASN.1 data and then perform float conversions such as printing, logging, or comparisons. The issue is fixed in pyasn1 version 0.6.4 and later.