CVE-2026-59886 is a denial-of-service vulnerability in the pyasn1 library affecting the univ.Real type. The issue arises when converting decoded ASN.1 REAL values with very large exponents to Python floats, causing excessive CPU and memory consumption that can hang the process. This affects operations such as printing, logging, comparing, or arithmetic on these decoded values. The vulnerability is fixed in pyasn1 versions 0.8.03 and 3.1.0_2.