Jwt Attack EUVD-2026-21899

Requires Cortex XSOAR or Cortex XSIAM with Microsoft Teams integration configured. Unauthenticated remote attacker must interact with the Teams integration endpoint. Attacker can bypass signature verification to access and modify protected resources. No victim interaction needed beyond having Teams integration active.

Real-world risk assessment reveals moderate-to-high priority despite the 7.2 CVSS score. The CVSS v4.0 vector indicates network attack vector (AV:N) with high attack complexity (AC:H) and present attack requirements (AT:P), requiring no privileges (PR:N) or user interaction (UI:N), with high confidentiality, integrity, and availability impacts on the vulnerable system. However, the attack complexity and specific requirements (proper timing, understanding of JWT implementation weaknesses) create practical exploitation barriers. No public exploit code has been identified at time of analysis, and the vulnerability is not listed in CISA KEV, indicating no confirmed active exploitation. The CVSS Exploit Maturity indicator shows 'Unreported' (E:U), and Recovery factor shows 'User' (R:U), suggesting controlled remediation window. The SSVC decision framework would classify this as medium priority: exploitation requires specific technical knowledge of JWT vulnerabilities, but the unauthenticated network access and high impact on protected resources elevate concern. Organizations using Microsoft Teams integrations with Cortex platforms should prioritize patching, while those without this specific integration face no exposure.

An unauthenticated attacker analyzes the Microsoft Teams integration API endpoints for Cortex XSOAR or XSIAM and identifies JWT-based authentication mechanisms. By crafting a malicious JWT with manipulated signature algorithms (such as algorithm confusion attacks or 'none' algorithm exploitation), the attacker bypasses cryptographic verification and presents a forged token to the integration endpoints. With successful authentication bypass, the attacker gains unauthorized access to protected SOAR/SIAM resources, potentially retrieving sensitive security orchestration data, modifying automation playbooks, or manipulating incident response workflows.