PraisonAI is a multi-agent teams system. Prior to 4.5.128, PraisonAI’s MCP (Model Context Protocol) integration allows spawning background servers via stdio using user-supplied command strings (e.g., MCP("npx -y @smithery/cli ...")). These commands are executed through Python’s subprocess module. By default, the implementation forwards the entire parent process environment to the spawned subprocess. As a result, any MCP command executed in this manner inherits all environment variables from the host process, including sensitive data such as API keys, authentication tokens, and database credentials. This behavior introduces a security risk when untrusted or third-party commands are used. In common scenarios where MCP tools are invoked via package runners such as npx -y, arbitrary code from external or potentially compromised packages may execute with access to these inherited environment variables. This creates a risk of unintended credential exposure and enables potential supply chain attacks through silent exfiltration of secrets. This vulnerability is fixed in 4.5.128.
CVE-2026-40159
MEDIUMNVD 5.55.5—Elevated
EchelonGraph scoreMEDIUM confidence
This medium-severity CVE scores 5.5 under NVD CVSS v3. EPSS exploit probability: 0.0%, top 95% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, nvd
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 5.5
- EG Score
- 5.5(medium)
- EPSS
- 7.9%
- KEV
- Not listed
Published
April 10, 2026
Last Modified
April 20, 2026
References (1)
- security-advisories@githubhttps://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-pj2r-f9mw-vrcq
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| praisonai | 0.0.1 ... 4.5.98 (685 versions) | 4.5.128 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Related CVEs(same CWE)
Same CWE
10 shownCWE-200
Frequently asked(5)
What is CVE-2026-40159?
CVE-2026-40159 is a medium vulnerability published on April 10, 2026. PraisonAI is a multi-agent teams system. Prior to 4.5.128, PraisonAI’s MCP (Model Context Protocol) integration allows spawning background servers via stdio using user-supplied command strings (e.g., MCP("npx -y @smithery/cli ...")). These commands are executed through Python’s subprocess module.…
When was CVE-2026-40159 disclosed?
CVE-2026-40159 was first published in the National Vulnerability Database on April 10, 2026, with the most recent update on April 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40159 actively exploited?
CVE-2026-40159 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 7.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-40159?
CVE-2026-40159 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-40159?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40159, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-40159
Is Your Infrastructure Affected by CVE-2026-40159?
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