CVE-2026-61459: mcp-server-kubernetes (PyPI)

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
EPSS 2.4%, percentile 84: FIRST’s model estimates a 2.4% chance of exploitation activity in the next 30 days, higher than 84% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
Only applies if your dependency tree includes mcp-server-kubernetes (PyPI) < 3.9.0, fixed in 3.9.0. Check your lockfile, including transitive dependencies.

What it is

MCP Server Kubernetes before 3.9.0 contains an argument injection vulnerability in structured tools (kubectlget, kubectldescribe, kubectldelete) that allows attackers to bypass the assertNoDangerousFlags security check by supplying resourceType and name parameters with leading dashes. Attackers can inject the --server flag to redirect kubectl commands to an attacker-controlled API server, causing the operator's bearer token to be transmitted externally and enabling full cluster compromise.

From the GitHub advisory

Weakness type: CWE-88.

Product: mcp-server-kubernetes (PyPI) · Assigned by: VulnCheck · Published: 2026-07-10

Affected and fixed versions

Ecosystem	Package	Vulnerable	First fixed
PyPI	`mcp-server-kubernetes`	< 3.9.0	3.9.0

Vendor	Product	Affected versions (per CVE record)
Flux159	mcp-server-kubernetes	< 3.9.0

Severity scores

Scored by	CVSS	Score	Vector
VulnCheck	4.0	9.3 Critical	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
VulnCheck	3.1	9.8 Critical	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
GitHub	4.0	9.3	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`

Attack vector: network (remotely reachable)
Attack complexity: low
Attack requirements: none
Privileges required: none (no login)
User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
FIRST EPSS (model of 2026-10-21): 2.36% probability of exploitation activity in the next 30 days; percentile 84.

Timeline

2026-07-10 — CVE record published by VulnCheck
2026-07-10 — GitHub-reviewed advisory GHSA-wmg3-h8mf-wgvr published (critical)
2026-07-14 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.