PraisonAI: Origin-validation bypass (startswith prefix match) enables unauthenticated cross-site request forgery against the PraisonAI MCP HTTP server

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.6 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:L

EPSS

• CVE-2026-55532: 0.20% estimated exploitation activity in the next 30 days; percentile 9.53 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The PraisonAI MCP server exposes an HTTP-stream transport (praisonai mcp serve --transport http-stream) that binds to localhost and, by default, has no API key. Its only access control for browser-originated requests is an Origin allowlist, which the code implements as required by the MCP 2025-11-25 security guidance. The allowlist check uses a prefix match (requestorigin.startswith(allowed)), so any Origin whose string begins with http://localhost or http://127.0.0.1 is accepted, for example http://localhost.attacker.com. An attacker who registers such a hostname and serves a page from it can, when a victim visits the page, issue cross-site requests that the MCP server accepts and executes without authentication. Because the request can be sent as a CORS "simple request" (Content-Type: text/plain, which the server still parses as JSON), it requires no preflight, and because tools/call does not require a session, a single forged request executes an MCP tool. This is a blind…

Published by the source

25 Aug 2026, 15:18 UTC

Last modified by the source

25 Aug 2026, 15:18 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-pvph-5j39-v8qc

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# Patch Next advisory brief: CVE-2026-55532

Advisory: PraisonAI: Origin-validation bypass (startswith prefix match) enables unauthenticated cross-site request forgery against the PraisonAI MCP HTTP server
IDs: CVE-2026-55532, GHSA-pvph-5j39-v8qc
Record: https://patchnext.com/advisories/cve-2026-55532 (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: praisonai 4.6.58. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI praisonai: affected < 4.6.58; fixed in 4.6.58

## Suggested inspection (read-only)
- `python -m pip show praisonai`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on praisonai.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-pvph-5j39-v8qc (GitHub-reviewed advisory GHSA-pvph-5j39-v8qc lists affected ranges: PyPI praisonai >=0 <4.6.58)

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