← Vulnerability feed

Vulnerability record · CVE-2026-39884 · published 15 April 2026

CVE-2026-39884: Suyogs mcp-server-kubernetes argument injection vulnerability

SSuyogs · Mcp Server Kubernetes

mcp-server-kubernetes is a Model Context Protocol server for Kubernetes cluster management. Versions 3.4.0 and prior contain an argument injection vulnerability in the port_forward tool in src/tools/port_forward.ts, where a kubectl command is constructed via string concatenation with user-controlled input and then naively split on spaces before being passed to spawn(). Unlike all other tools in the codebase which correctly use array-based argument passing with execFileSync(), port_forward treats every space in user-controlled fields (namespace, resourceType, resourceName, localPort, targetPort) as an argument boundary, allowing an attacker to inject arbitrary kubectl flags. This enables exposure of internal Kubernetes services to the network by injecting --address=0.0.0.0, cross-namespace targeting by injecting additional -n flags, and indirect exploitation via prompt injection against AI agents connected to the MCP server. This issue has been fixed in version 3.5.0.

8.1 CVSS 3.1 High EPSS 0.42% · top 66.6% CWE-88 · Argument injection
8.1CVSS 3.1 base score
0.42%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References
17 Jun 2026Last modified by NVD

Description

mcp-server-kubernetes is a Model Context Protocol server for Kubernetes cluster management. Versions 3.4.0 and prior contain an argument injection vulnerability in the port_forward tool in src/tools/port_forward.ts, where a kubectl command is constructed via string concatenation with user-controlled input and then naively split on spaces before being passed to spawn(). Unlike all other tools in the codebase which correctly use array-based argument passing with execFileSync(), port_forward treats every space in user-controlled fields (namespace, resourceType, resourceName, localPort, targetPort) as an argument boundary, allowing an attacker to inject arbitrary kubectl flags. This enables exposure of internal Kubernetes services to the network by injecting --address=0.0.0.0, cross-namespace targeting by injecting additional -n flags, and indirect exploitation via prompt injection against AI agents connected to the MCP server. This issue has been fixed in version 3.5.0.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/Flux159/mcp-server-kubernetes/releases/tag/v3.5.0 ProductRelease Notes
https://github.com/Flux159/mcp-server-kubernetes/security/advisories/GHSA-4xqg-gf5c-ghwq MitigationVendor Advisory
https://github.com/Flux159/mcp-server-kubernetes/security/advisories/GHSA-4xqg-gf5c-ghwq MitigationVendor Advisory

Track CVE-2026-39884 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.3CVE-2026-61459Suyogs mcp-server-kubernetes argument injection vulnerabilityMCP Server Kubernetes before 3.9.0 contains an argument injection vulnerability in structured tools (kubectl_get, kubectl_describe, kubectl_delete) t…EPSS 2.4%8.8CVE-2025-66404Suyogs mcp-server-kubernetes command injection vulnerabilityMCP Server Kubernetes is an MCP Server that can connect to a Kubernetes cluster and manage it. Prior to 2.9.8, there is a security issue exists in th…EPSS 1.5%9.2CVE-2026-86060MikroTik RouterOS SSH login argument injection privilege escalationRouterOS mishandles arguments in the SSH login path when a username begins with a prohibited character, allowing the trusted policy mask to be altere…KEVEPSS 1.8%analysed9.8CVE-2026-24061GNU Inetutils telnetd argument injection allows remote auth bypasstelnetd in GNU Inetutils through 2.7 fails to sanitize the USER environment variable, so a value such as "-f root" is passed as an argument to login …KEVEPSS 99%analysed9.8CVE-2016-10033PHPMailer isMail mailSend argument injection enables remote code executionPHPMailer before 5.2.18 fails to properly sanitize the Sender property in the mailSend function of the isMail transport, allowing a crafted backslash…KEVEPSS 100%analysed7.2CVE-2024-41710Mitel SIP Phones argument injection in boot processMitel 6800, 6900 and 6900w Series SIP Phones (including the 6970 Conference Unit) through R6.4.0.HF1 fail to sanitize parameters during the boot proc…KEVEPSS 42%analysed8.8CVE-2022-36804Atlassian Bitbucket Server and Data Center API command injectionMultiple API endpoints in Atlassian Bitbucket Server and Data Center fail to properly neutralize command and argument input, allowing OS command inje…KEVEPSS 99%analysed

Source: NIST National Vulnerability Database (record CVE-2026-39884), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.