The pyasn1 library contains an uncontrolled recursion vulnerability that allows unauthenticated attackers to cause a Denial of Service by supplying specially crafted ASN.1 payloads.

This is a CWE-674 Uncontrolled Recursion flaw where the decoder fails to limit stack depth when processing nested SEQUENCE or SET tags. An unauthenticated attacker can trigger a RecursionError or Out of Memory condition by providing malicious input.

Successful exploitation results in the crash of any application utilizing the pyasn1 library for ASN.1 decoding. Given the CVSS score of 7.5, this high severity vulnerability poses a significant risk to service availability, potentially disrupting critical business operations that rely on network protocol parsing or cryptographic data handling.

Immediate Action: Update the pyasn1 package to version 0.6.3 or later to incorporate the recursive depth limits.

Proactive Monitoring: Monitor application logs for frequent RecursionError exceptions or sudden spikes in memory consumption that correlate with incoming network traffic.

Compensating Controls: Implement input validation or size limits on incoming ASN.1 data at the application gateway level to prevent excessively nested structures from reaching the parser.

Public Exploit Available: No.

The vulnerability represents a clear risk to system availability and reliability. Security teams must prioritize upgrading all instances of the pyasn1 library to version 0.6.3 immediately to eliminate the recursion risk, as the lack of authentication requirements makes this an attractive target for automated Denial of Service attempts.