Is CVE-2026-39884 in the CISA KEV catalog?

No. CVE-2026-39884 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-39884?

CVE-2026-39884 has a CVSS v3 base score of 8.3 (HIGH).

What is the EPSS score for CVE-2026-39884?

CVE-2026-39884 has an EPSS score of 0.26% (17th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-39884

HIGH

8.3

CVSS v3

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.

CWE-88

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityLow

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

Exploit Intelligence

0.26%probability of exploitation in 30 days

17thpercentile

Low risk: more likely to be exploited than 17% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-23.