Neethi WS-Policy Stack Exhaustion Denial of Service

CVE-2026-91863 is a denial-of-service vulnerability in Apache Neethi's WS-Policy parser that allows attackers to crash the parser through specially crafted XML documents containing deeply nested policy elements. The vulnerability exploits insufficient nesting-depth validation, permitting malicious actors to exhaust thread stack resources and trigger application crashes. This affects any system using Neethi versions prior to 3.2.4 for WS-Policy processing, including web services frameworks and SOAP implementations that rely on Neethi for policy enforcement. Organizations deploying WS-Policy-dependent architectures face service disruption and potential cascading failures in dependent systems.

While this CVE does not map directly to MITRE ATT&CK techniques, Casky's security skills suite would detect attack patterns through analysis of CWE-674 (Uncontrolled Recursion) indicators and resource exhaustion behaviors. Practitioners using Casky would identify suspicious WS-Policy document submissions characterized by abnormal XML nesting depths, unusual thread consumption spikes, and parser crash logs. Claude AI's extended reasoning capabilities enable detection of structural parsing anomalies and malformed input patterns that deviate from legitimate WS-Policy specifications. Security teams would see findings flagged around input validation failures, uncontrolled resource consumption, and denial-of-service precursors—allowing proactive patching and WAF rule deployment before exploitation occurs.