CVE-2026-119194 is a high-severity vulnerability in pyasn1's schemaless BER, CER, and DER decoding that causes quadratic CPU usage when decoding attacker-controlled data with many distinct long tag IDs. This can lead to CPU exhaustion and reduced service availability. The issue arises because the decoder unnecessarily grows a set of tag identifiers, causing performance degradation with crafted inputs. No confidentiality or integrity impacts are reported.