CVE-2026-55529 PraisonAI has an origin validation bypass in MCP HTTP Stream transport that allows browser-mediated unauthenticated tool execution on local MCP server
Attackers can bypass origin validation to execute tools on local MCP servers via malicious webpages, requiring an upgrade to PraisonAI.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-55529?
CVE-2026-55529 is a medium-severity authentication bypass vulnerability in MervinPraison PraisonAI, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Which versions are affected by CVE-2026-55529?
3 open source packages ship an affected version, including praisonai and PraisonAI.
| Package | Affected | Fixed in |
|---|---|---|
praisonai PyPI | All versions | 4.6.58 |
praisonai PyPI | All versions | 4.6.58 |
PraisonAI PyPI | All versions | 4.6.58 |
How do I fix CVE-2026-55529?
Upgrade praisonai to 4.6.58 or later.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-55529 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55529 exists.
Sources
Also known as GHSA-wj6g-v78p-6fx3, PYSEC-2026-3896.