Medium severity · published Aug 25, 2026
CVE-2026-55529
PraisonAI: Origin validation bypass in MCP HTTP Stream transport allows browser-mediated unauthenticated tool execution on local MCP server
6.9
CVSS
0.2%
EPSS
No
On KEV
Description
PraisonAI is a multi-agent teams system. Prior to praisonai 4.6.58, the MCP HTTP Stream _validate_origin method accepts request_origin.startswith(allowed), so the attacker-controlled localhost.evil.example HTTP origin matches the localhost allowlist. Without an API key, a malicious webpage can submit tools/call requests to the local MCP server and execute exposed tools. This issue is fixed in version 4.6.58.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 7% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PR
PraisonAI · MervinPraison
< 4.6.58 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-55529
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-55529
github.com
https://github.com/MervinPraison/PraisonAI/commit/2f9677abb2ea68eab864ee8b6a828fd0141612e1
github.com
https://github.com/MervinPraison/PraisonAI/releases/tag/v4.6.58
github.com
https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-wj6g-v78p-6fx3
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