CVE-2026-55531 MervinPraison CVE debrief

Who should care

Defenders responsible for PraisonAI deployments should assess exposure and apply the fix to prevent potential memory exhaustion attacks. This includes verifying PraisonAI versions, implementing PRAISONAI_MCP_MAX_SESSIONS, and monitoring for potential memory exhaustion attacks. Security teams and vulnerability management teams should also review compensating controls for exposed systems while remediation is scheduled and verified.

Why it matters

CVE-2026-55531 is a vulnerability in PraisonAI that can lead to memory exhaustion. Defenders should prioritize verifying PraisonAI versions and applying the fix to prevent potential memory exhaustion attacks. The issue is fixed in version 4.6.58, which invokes cleanup and limits sessions through PRAISONAI_MCP_MAX_SESSIONS.

• Memory exhaustion can occur due to lack of session limits and cleanup.
• Unauthenticated attackers can exploit this vulnerability to consume memory.
• Fixing the issue requires updating to version 4.6.58 or implementing PRAISONAI_MCP_MAX_SESSIONS.
• Verification of PraisonAI versions and exposure is necessary.

Technical summary

The MCP HTTP Stream mcp_post handler in PraisonAI creates a new _sessions entry for every initialize request without proper cleanup or session limits, allowing an unauthenticated attacker to consume memory. The issue is fixed in version 4.6.58, which invokes cleanup and limits sessions through PRAISONAI_MCP_MAX_SESSIONS. This vulnerability can lead to memory exhaustion, emphasizing the need for defenders to verify PraisonAI versions and apply the fix to prevent potential memory exhaustion attacks. Affected PraisonAI deployments should prioritize verification and remediation.

Defensive priority

Defenders should prioritize verifying PraisonAI versions and applying the fix to prevent potential memory exhaustion attacks.

Recommended defensive actions

• Verify PraisonAI version and apply fix if necessary
• Implement PRAISONAI_MCP_MAX_SESSIONS to limit sessions
• Monitor for potential memory exhaustion attacks
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, its impact, and the fix. However, the corpus does not establish versions, exploitation, impact, or remediation beyond the provided information, requiring verification from official sources.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.