🟠 High | Source: Microsoft Security Response Center
CVE-2026-59884 is a denial-of-service vulnerability in pyasn1, a Python library used to encode and decode ASN.1 data structures. An attacker can craft malicious input with unbounded long-form tag IDs to exhaust resources in the BER/CER/DER decoder, potentially crashing dependent services. This matters because pyasn1 is widely used in cryptographic and certificate-handling workflows across cloud-hosted Python applications.
Security Architect’s Take: Audit your Azure-hosted Python workloads and pipelines for direct or transitive dependencies on pyasn1, then update to the patched version as soon as it is available. Pay particular attention to services that process externally supplied certificates, SNMP data, or ASN.1-encoded inputs from untrusted sources.
Original advisory: CVE-2026-59884 pyasn1 BER/CER/DER decoder denial of service via unbounded long-form tag IDs