CVE-2026-40159

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.5 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 92% 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
Elevated
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.5Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
5.5
EG Score
5.5MEDIUMmedium confidence
EG Risk
41
EG Risk 41/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation40% × 40%
Automatability0% × 15%
EPSS PROB
0.2%
EPSS %ILE
7th
KEV
Not listed

Published

April 10, 2026

Last Modified

April 20, 2026

Advisory Details (1)

Auto-updated Aug 2, 2026
🔬 Proof of concept available. Patch available. Sources: github.
githubMentions a patch (unverified)🟡 PoC Available

Sensitive Environment Variable Exposure via Untrusted MCP Subprocess Execution · Advisory · MervinPraison/PraisonAI · GitHub

https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-pj2r-f9mw-vrcq

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
praisonai0.0.1 ... 4.5.98 (685 versions)
  • every version up to 4.5.128: fixed in 4.5.128
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 25× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 169 total refreshes for this CVE.

  1. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-08 17:12 UTCEPSS rescore
  3. 2026-10-07 23:48 UTCEPSS rescore
  4. 2026-10-06 15:17 UTCEPSS rescore
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  10. 2026-09-27 13:48 UTCEPSS rescore
  11. 2026-09-26 15:58 UTCEPSS rescore
  12. 2026-09-26 00:26 UTCEPSS rescore
  13. 2026-09-21 08:19 UTCOSV refresh
  14. 2026-09-20 20:15 UTCEPSS rescore
  15. 2026-09-18 19:28 UTCEPSS rescore
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  1. 2026-09-08 22:00 UTCEPSS rescore
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  3. 2026-09-06 13:47 UTCEPSS rescore
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  5. 2026-09-02 14:12 UTCEPSS rescore
  6. 2026-09-02 06:14 UTCOSV refresh
  7. 2026-09-01 13:53 UTCEPSS rescore
  8. 2026-09-01 04:39 UTCEPSS rescore
  9. 2026-08-30 19:17 UTCEPSS rescore
  10. 2026-08-30 01:22 UTCEPSS rescore
  11. 2026-08-28 21:41 UTCEPSS rescore
  12. 2026-08-27 14:25 UTCEPSS rescore
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  19. 2026-08-18 13:48 UTCEPSS rescore
  20. 2026-08-17 13:47 UTCEPSS rescore
  21. 2026-08-16 14:56 UTCEPSS rescore
  22. 2026-08-16 07:01 UTCEG score recompute
  23. 2026-08-16 02:14 UTCEPSS rescore
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  25. 2026-08-14 05:01 UTCEG score recompute
  26. 2026-08-13 22:00 UTCEPSS rescore
  27. 2026-08-12 23:56 UTCEG score recompute
  28. 2026-08-12 13:51 UTCEPSS rescore
  29. 2026-08-12 01:26 UTCEG score recompute
  30. 2026-08-11 13:43 UTCEPSS rescore
  31. 2026-08-11 02:56 UTCEG score recompute
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  36. 2026-08-08 16:37 UTCEPSS rescore
  37. 2026-08-07 14:17 UTCEG score recompute
  38. 2026-08-06 13:46 UTCEPSS rescore
  39. 2026-08-05 23:39 UTCEG score recompute
  40. 2026-08-05 19:17 UTCEPSS rescore
  41. 2026-08-04 15:10 UTCEPSS rescore
  42. 2026-08-04 10:38 UTCEPSS rescore
  43. 2026-08-03 21:54 UTCEG score recompute
  44. 2026-08-03 10:36 UTCEPSS rescore
  45. 2026-08-02 13:41 UTCEG score recompute
  46. 2026-08-02 02:27 UTCEPSS rescore
  47. 2026-08-01 04:16 UTCEPSS rescore
  48. 2026-07-30 16:28 UTCEPSS rescore
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  50. 2026-07-27 14:13 UTCEPSS rescore
  51. 2026-07-26 14:54 UTCEPSS rescore
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  57. 2026-07-23 14:18 UTCEPSS rescore
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  59. 2026-07-23 03:11 UTCEG score recompute
  60. 2026-07-22 14:08 UTCEPSS rescore
  61. 2026-07-21 15:24 UTCEPSS rescore
  62. 2026-07-20 19:32 UTCOSV refresh
  63. 2026-07-20 17:08 UTCEPSS rescore
  64. 2026-07-19 14:31 UTCEPSS rescore
  65. 2026-07-19 02:29 UTCEPSS rescore
  66. 2026-07-18 10:04 UTCEPSS rescore
  67. 2026-07-16 17:03 UTCEPSS rescore
  68. 2026-07-15 16:57 UTCEPSS rescore
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  71. 2026-07-13 22:30 UTCEPSS rescore
  72. 2026-07-13 06:13 UTCEPSS rescore
  73. 2026-07-13 06:13 UTCEPSS rescore
  74. 2026-07-12 05:46 UTCEPSS rescore
  75. 2026-07-11 08:27 UTCEPSS rescore

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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 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 0.2% probability of exploitation in the next 30 days (7th percentile of EPSS-scored CVEs).
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?
A fix for CVE-2026-40159 is available: update to the fixed version the vendor names in its advisory.

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