Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2026-23744

REC in MCPJam inspector due to HTTP Endpoint exposes

MCPJam / inspector · <= 1.4.2

Watch CVE-2026-23744 Browse KEV feed
Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
67.5%
First observed
03 Jul 2026
Last observed
18 Oct 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-23744 is an unauthenticated REC in MCPJam inspector due to HTTP Endpoint exposes. MCPJam inspector is the local-first development platform for MCP servers. Versions 1.4.2 and earlier are vulnerable to remote...

Is it exploited?

Yes. Previdian sensors observed exploitation attempts with confirmed confidence. Also confirmed by third-party sources.

Who is affected?

MCPJam / inspector <= 1.4.2.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

MCPJam inspector is the local-first development platform for MCP servers

MCPJam inspector is the local-first development platform for MCP servers. Versions 1.4.2 and earlier are vulnerable to remote code execution (RCE) vulnerability, which allows an attacker to send a crafted HTTP request that triggers the installation of an MCP server, leading to RCE.

Since MCPJam inspector by default listens on 0.0.0.0 instead of 127.0.0.1, an attacker can trigger the RCE remotely via a simple HTTP request. Version 1.4.3 contains a patch.

MCPJam Affected
inspector
<= 1.4.2
Published
16 Jan 2026
Exploitation Reported
03 Apr 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

nuclei_scanner

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

The Shadowserver

Recorded 03 Apr 2026

A trusted third party reported exploitation.

Active exploitation observed

Previdian sensor

First observed 03 Jul 2026

Previdian first observed exploitation attempts targeting this vulnerability in our honeypot sensors.

Proof of concept available

Nuclei Templates

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
The Shadowserver First 2026-04-03 00:00 UTC
Previdian Sensors 2026-07-30 16:09 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Previdian sensors recorded exploitation attempts targeting this vulnerability. The cards and chart show volume, unique attackers, and daily activity.

27

Attempts observed

15

Unique attacker IPs

10

Attacker countries

AF · BG · CH · FR · ID · IR · JP · NL · SC · US

17

Sensors observed

CVE-2026-23744 exploitation attempts over the last 89 days

Daily events observed by Previdian sensors

Updated 19 Oct 2026

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0
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0
0
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23 Jul 10 Aug 28 Aug 15 Sep 19 Oct

First observed 03 Jul 2026 · Last observed 18 Oct 2026

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
1
9
1

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-23744.yaml 01 Jun 2026

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

9.8 Critical

Potential damage if exploited. Separate from whether attackers are using it.

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

EPSS

67.5%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Missing Authentication for Critical Function CWE-306

Recent mention · Rapid7

Metasploit Wrap Up: This One Goes to Sixteen!

This One Goes to Sixteen!Another banger from Metasploit with sixteen new modules, including ten exploit modules, with five on the CISA KEV list. Cisco, Papercut, Sonicwall, Jetbrains, and Langflow all have exploit modules, and not to be outdone, we even have a Metasploit...

Read full advisory

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

01xJB/CVE-2026-23744-POC

github · Created 2026-10-07 14:58:12 UTC · 0 stars · AI assessment 90%

MCPJam Inspector Remote Code Execution

wvverez/CVE-2026-23744

github · Created 2026-09-17 15:57:13 UTC · 1 stars · AI assessment 85%

exploit para reverse shell en MCPJamInspector v1.4.2< por endpoint mal configurado

sonnelon/CVE-2026-23744-PoC

github · Created 2026-08-10 15:57:48 UTC · 0 stars · AI assessment 90%

Mluex0/CVE-2026-23744-PoC

github · Created 2026-08-10 09:07:16 UTC · 0 stars · AI assessment 90%

CVE-2026-23744 is an unauthenticated command injection in MCPJam Inspector ≤1.4.2 via /api/mcp/connect. This POC exploits it by sending a crafted JSON payload to execute arbitrary commands, granting a reverse shell with PTY.

MCPJam Inspector - Remote Code Execution

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

  1. 04:22 UTC

    Indicators of compromise added (22)

    Indicators of compromise recorded

  2. 04:22 UTC

    Observed by Previdian sensors

    Evidence-backed exploitation signal

  3. 14:21 UTC

    Public PoC available

    Public proof-of-concept code published

  4. 15:34 UTC

    Nuclei template available

    Scanner coverage available

  5. 00:00 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party attested exploitation

  6. 20:10 UTC

    CVE published

    Vulnerability disclosed publicly

  7. 15:45 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-23744

Sample API response 
{
  "cve_id": "CVE-2026-23744",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.67516,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 27, "sensors": 17 }
}