CVE-2026-55531

Name of the Vulnerable Software and Affected Versions PraisonAI versions prior to 4.6.58

Description The MCP HTTP Stream mcp post handler fails to enforce a maximum number of sessions and does not invoke the cleanup sessions() function to expire old entries. Consequently, every initialize request creates a new in-memory session that is never removed. Additionally, the notifications/cancelled endpoint populates a cancelled requests set that is never pruned. Since the initialize request is unauthenticated, a remote attacker can send repeated requests to exhaust system memory, leading to a denial of service when the process is terminated by the out-of-memory killer. This issue is further amplified by the fact that the server retains SSE event history for each session.

Recommendations Update to version 4.6.58. As a temporary mitigation, restrict access to the mcp post handler or the notifications/cancelled endpoint to trusted sources only. Configure the PRAISONAI MCP MAX SESSIONS variable to limit the number of concurrent sessions.