NVD / CVE Program· CNA kubernetes

CVE-2020-8557: Kubernetes node disk Denial of Service by writing to container /etc/hosts

Noroxi assessment

Priority: Monitor (action score 22/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.43% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: kubernetes (Debian:12) 1.18.5-1; k8s.io/kubernetes (Go) 1.16.13, 1.17.9, 1.18.6; k8s.io/kubernetes/pkg/kubelet (Go) 1.16.13, 1.17.9, 1.18.6.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to kubernetes (Debian:12) 1.18.5-1; k8s.io/kubernetes (Go) 1.16.13, 1.17.9, 1.18.6; k8s.io/kubernetes/pkg/kubelet (Go) 1.16.13, 1.17.9, 1.18.6 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

The Kubernetes kubelet component in versions 1.1-1.16.12, 1.17.0-1.17.8 and 1.18.0-1.18.5 do not account for disk usage by a pod which writes to its own /etc/hosts file. The /etc/hosts file mounted in a pod by kubelet is not included by the kubelet eviction manager when calculating ephemeral storage usage by a pod. If a pod writes a large amount of data to the /etc/hosts file, it could fill the storage space of the node and cause the node to fail.

MediumCVSS 5.5 · v3.1—No exploit Fix available

Denial of service

Published: Jul 23, 2020
Updated: Jun 16, 2026
EPSS: 0.4% · 37th percentile
CWE: CWE-400

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 22 / 40 · 5.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CNA vs NVD score

NVD: 5.5
CNA · kubernetes: 5.5; agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
kubernetes	kubernetes	cpe:2.3:a:kubernetes:kubernetes

Using kubernetes? Add it to your stack and be the first to know about CVEs like this one. (Kubernetes)

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

kubernetes kubernetesbefore 1.16.13
kubernetes kubernetes1.17.0 and later · before 1.17.9
kubernetes kubernetes1.18.0 and later · before 1.18.6

Versions reported by the vendor

Affected version ranges reported by the assigning authority (kubernetes). Independent of NVD's CPE analysis and usually ahead of it.

Kubernetes Kubernetes
- 1.15, 1.14, 1.13, 1.12, 1.11, 1.10, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4 … (+3)affected
- 1.18 and later · before 1.18.6affected
- 1.17 and later · before 1.17.9affected
- 1.16 and later · before 1.16.13affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

+10

Same product

kubernetes: all records

Other highest-scoring records for the same primary product.

CVE-2018-1002105In all Kubernetes versions prior to v1.10.11, v1.11.5, and v1.12.3, incorrect handling of error responses to proxied upgrade requests in the
65This week
CVE-2019-11248Kubernetes kubelet exposes /debug/pprof info on healthz port
55Plan
CVE-2017-1002101In Kubernetes versions 1.3.x, 1.4.x, 1.5.x, 1.6.x and prior to versions 1.7.14, 1.8.9 and 1.9.4 containers using subpath volume mounts with
42Plan

Published before and after this one in the same product

← EarlierCVE-2020-8559Jul 22, 2020 · Privilege escalation from compromised node to cluster
29Monitor
← EarlierCVE-2019-11252Jul 23, 2020 · Credential leakage when failing to mount
26Monitor
Later →CVE-2020-8558Jul 27, 2020 · Kubernetes node setting allows for neighboring hosts to bypass localhost boundary
36Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
debian:kubernetes	1.18.5-1 · Debian:12	Package registry (OSV)
Go:k8s.io/kubernetes	1.16.13	Package registry (OSV)
Go:k8s.io/kubernetes	1.17.9	Package registry (OSV)
Go:k8s.io/kubernetes	1.18.6	Package registry (OSV)
Go:k8s.io/kubernetes/pkg/kubelet	1.16.13	Package registry (OSV)
Go:k8s.io/kubernetes/pkg/kubelet	1.17.9	Package registry (OSV)
Go:k8s.io/kubernetes/pkg/kubelet	1.18.6	Package registry (OSV)
opensuse:govulncheck-vulndb	0.0.20250807T150727-1.1 · openSUSE:Tumbleweed	Package registry (OSV)
red hat:atomic-openshift	0:3.11.542-1.git.0.f2fd300.el7 · Red Hat:openshift:3.11::el7	Package registry (OSV)
red hat:atomic-openshift-clients	0:3.11.542-1.git.0.f2fd300.el7 · Red Hat:openshift:3.11::el7	Package registry (OSV)
red hat:atomic-openshift-clients-redistributable	0:3.11.542-1.git.0.f2fd300.el7 · Red Hat:openshift:3.11::el7	Package registry (OSV)
red hat:atomic-openshift-docker-excluder	0:3.11.542-1.git.0.f2fd300.el7 · Red Hat:openshift:3.11::el7	Package registry (OSV)
red hat:atomic-openshift-excluder	0:3.11.542-1.git.0.f2fd300.el7 · Red Hat:openshift:3.11::el7	Package registry (OSV)
red hat:atomic-openshift-hyperkube	0:3.11.542-1.git.0.f2fd300.el7 · Red Hat:openshift:3.11::el7	Package registry (OSV)
red hat:atomic-openshift-hypershift	0:3.11.542-1.git.0.f2fd300.el7 · Red Hat:openshift:3.11::el7	Package registry (OSV)
red hat:atomic-openshift-master	0:3.11.542-1.git.0.f2fd300.el7 · Red Hat:openshift:3.11::el7	Package registry (OSV)
red hat:atomic-openshift-node	0:3.11.542-1.git.0.f2fd300.el7 · Red Hat:openshift:3.11::el7	Package registry (OSV)
red hat:jenkins	0:2.235.2.1597312414-1.el7 · Red Hat:openshift:4.5::el7	Package registry (OSV)
red hat:openshift	0:4.5.0-202008130146.p0.git.0.aaf1d57.el7 · Red Hat:openshift:4.5::el7	Package registry (OSV)
red hat:openshift-hyperkube	0:4.5.0-202008130146.p0.git.0.aaf1d57.el7 · Red Hat:openshift:4.5::el7	Package registry (OSV)
suse:kubernetes	1.17.4-4.18.1 · SUSE:Linux Enterprise Module for Containers 15 SP1	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Kebe LiuDaoCloud

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-20-797 · Sep 30, 2020(IBM Cloud Private Güvenlik Güncellemesi)

All national notices →

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

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

nvd-primary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log

Fix✗ → ✓Sep 28, 2026, 10:45 PM UTC

For records you follow, these changes also arrive as notifications. →

References

github.com/kubernetes/kubernetes/issues/93032

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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