CVE-2026-55529: CWE-306: Missing Authentication for Critical Function in MervinPraison PraisonAI
Description
CVE-2026-55529 is a vulnerability in MervinPraison's PraisonAI multi-agent teams system prior to version 4.6.58. The issue arises because the MCP HTTP Stream _validate_origin method incorrectly validates origins by using a startswith check, allowing attacker-controlled origins like localhost.evil.example to bypass the localhost allowlist. This enables a malicious webpage to submit requests to the local MCP server without an API key and execute exposed tools. The vulnerability is fixed in version 4.6.58.
CVSS v3.1
Score 6.9medium
Affected software
MervinPraison
PraisonAI
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
PraisonAI versions before 4.6.58 contain a missing authentication vulnerability (CWE-306) in the MCP HTTP Stream _validate_origin method. The method uses a startswith check on the request origin against allowed origins, which can be bypassed by crafted origins such as localhost.evil.example. This flaw allows unauthorized web pages to send tools/call requests to the local MCP server without requiring an API key, potentially leading to unauthorized execution of exposed tools. The issue is resolved in version 4.6.58.
Potential Impact
An attacker can bypass origin validation and submit unauthorized requests to the local MCP server without an API key, enabling execution of exposed tools. This results in high confidentiality impact due to unauthorized access, limited integrity impact, and no availability impact. The CVSS 3.1 base score is 6.9 (medium severity).
Mitigation Recommendations
Upgrade PraisonAI to version 4.6.58 or later, where the vulnerability is fixed. No other mitigation is indicated by the vendor advisory. Patch status is confirmed fixed in 4.6.58.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-16T23:01:04.073Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a8da8bcacd9273b4950d982
Added to database: 08/25/2026, 14:37:48 UTC
Last enriched: 09/10/2026, 18:25:58 UTC
Last updated: 10/09/2026, 18:48:21 UTC
Views: 63
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