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NVD / CVE Program· CNA kubernetes

CVE-2020-8559: Privilege escalation from compromised node to cluster

Noroxi assessment

Priority: Monitor (action score 29/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 6.1% (FIRST EPSS); higher than 93.4% of all records.
  • Anyone who can reach it over the internet can trigger it. Administrator privileges are required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: kubernetes (Debian:12) 1.18.5-1; k8s.io/apimachinery (Go) 0.17.9, 0.18.7-rc.0, 0.18.7; k8s.io/kubernetes (Go) 1.17.9, 1.18.7, 1.16.13.
  • Mentioned 2 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to kubernetes (Debian:12) 1.18.5-1; k8s.io/apimachinery (Go) 0.17.9, 0.18.7-rc.0, 0.18.7; k8s.io/kubernetes (Go) 1.17.9, 1.18.7, 1.16.13 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 kube-apiserver in versions v1.6-v1.15, and versions prior to v1.16.13, v1.17.9 and v1.18.6 are vulnerable to an unvalidated redirect on proxied upgrade requests that could allow an attacker to escalate privileges from a node compromise to a full cluster compromise.

MediumCVSS 6.8 · v3.1—Proof of concept Fix available
Published
Jul 22, 2020
Updated
Jun 16, 2026
EPSS
6.1% · 93th percentile

Report tools

JSON

Action score

29

Monitor

Low priority for now.

CVSS
27 / 40 · 6.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
2 / 30 · 6.1%

CNA vs NVD score

NVD
6.8
CNA · kubernetes
6.4
0.4 point gap

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

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
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

VendorProduct
kuberneteskubernetes

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When you'll hear from us

  • when a new CVE affecting this product is published
  • when a record in your stack enters KEV or gets exploit code

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  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
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Affected versions

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

  • kubernetes kubernetes1.6.0 and later · up to 1.15.0 inclusive
  • kubernetes kubernetes1.16.0 and later · before 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

    • 1.6, 1.7, 1.8, 1.9, 1.10, 1.11, 1.12, 1.13, 1.14, 1.15affected
    • 1.16 and later · up to and including 1.16.12affected
    • 1.17 and later · up to and including 1.17.8affected
    • 1.18 and later · up to and including 1.18.5affected

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12kubernetesbefore 1.18.5-11.18.5-1
Gok8s.io/apimachineryfrom 0.17.0 · before 0.17.90.17.9
Gok8s.io/apimachineryfrom 0.18.0 · before 0.18.7-rc.00.18.7-rc.0
Gok8s.io/apimachineryfrom 0.18.0 · before 0.18.70.18.7
Gok8s.io/apimachinerybefore 0.16.130.16.13
Gok8s.io/kubernetesfrom 1.17.0 · before 1.17.91.17.9
Gok8s.io/kubernetesfrom 1.18.0 · before 1.18.71.18.7
Gok8s.io/kubernetesbefore 1.16.131.16.13
Red Hat:openshift:3.11::el7atomic-openshiftbefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-clientsbefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-clients-redistributablebefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-docker-excluderbefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-excluderbefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-hyperkubebefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-hypershiftbefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-masterbefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-nodebefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-podbefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-sdn-ovsbefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-template-service-brokerbefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:3.11::el7atomic-openshift-testsbefore 0:3.11.346-1.git.0.ea10721.el70:3.11.346-1.git.0.ea10721.el7
Red Hat:openshift:4.4::el7openshiftbefore 0:4.4.0-202012052258.p0.git.0.0fd57a4.el70:4.4.0-202012052258.p0.git.0.0fd57a4.el7
Red Hat:openshift:4.4::el7openshift-hyperkubebefore 0:4.4.0-202012052258.p0.git.0.0fd57a4.el70:4.4.0-202012052258.p0.git.0.0fd57a4.el7
Red Hat:openshift:4.4::el8openshiftbefore 0:4.4.0-202012052258.p0.git.0.0fd57a4.el80:4.4.0-202012052258.p0.git.0.0fd57a4.el8

+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-2019-11254Apr 1, 2020 · Kubernetes API Server denial of service vulnerability from malicious YAML payloads
    27Monitor
  • ← EarlierCVE-2020-8555Jun 5, 2020 · Kubernetes kube-controller-manager SSRF
    26Monitor
  • Later →CVE-2019-11252Jul 23, 2020 · Credential leakage when failing to mount
    26Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
debian:kubernetes1.18.5-1 · Debian:12Package registry (OSV)
Go:k8s.io/apimachinery0.16.13Package registry (OSV)
Go:k8s.io/apimachinery0.17.9Package registry (OSV)
Go:k8s.io/apimachinery0.18.7Package registry (OSV)
Go:k8s.io/apimachinery0.18.7-rc.0Package registry (OSV)
Go:k8s.io/kubernetes1.16.13Package registry (OSV)
Go:k8s.io/kubernetes1.17.9Package registry (OSV)
Go:k8s.io/kubernetes1.18.7Package registry (OSV)
red hat:atomic-openshift0:3.11.346-1.git.0.ea10721.el7 · Red Hat:openshift:3.11::el7Package registry (OSV)
red hat:atomic-openshift-clients0:3.11.346-1.git.0.ea10721.el7 · Red Hat:openshift:3.11::el7Package registry (OSV)
red hat:atomic-openshift-clients-redistributable0:3.11.346-1.git.0.ea10721.el7 · Red Hat:openshift:3.11::el7Package registry (OSV)
red hat:atomic-openshift-docker-excluder0:3.11.346-1.git.0.ea10721.el7 · Red Hat:openshift:3.11::el7Package registry (OSV)
red hat:atomic-openshift-excluder0:3.11.346-1.git.0.ea10721.el7 · Red Hat:openshift:3.11::el7Package registry (OSV)
red hat:ignition0:2.6.0-5.rhaos4.6.git947598e.el8 · Red Hat:openshift:4.6::el8Package registry (OSV)
red hat:ignition-debuginfo0:2.6.0-5.rhaos4.6.git947598e.el8 · Red Hat:openshift:4.6::el8Package registry (OSV)
red hat:ignition-debugsource0:2.6.0-5.rhaos4.6.git947598e.el8 · Red Hat:openshift:4.6::el8Package registry (OSV)
red hat:ignition-validate0:2.6.0-5.rhaos4.6.git947598e.el8 · Red Hat:openshift:4.6::el8Package registry (OSV)
red hat:ignition-validate-debuginfo0:2.6.0-5.rhaos4.6.git947598e.el8 · Red Hat:openshift:4.6::el8Package registry (OSV)
red hat:openshift0:4.6.0-202010022112.p0.git.94033.ef41184.el7 · Red Hat:openshift:4.6::el7Package registry (OSV)
red hat:openshift-hyperkube0:4.6.0-202010022112.p0.git.94033.ef41184.el7 · Red Hat:openshift:4.6::el7Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×2

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:202020-07-22
Proof-of-concept repository on GitHubstars:532020-07-22

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.

  1. First PoCsame day
  2. Published
  3. TodayNov 3, 2026+2296 d

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.

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.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • Administrator privileges are required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
Required
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-601 · URL Redirection to Untrusted Site ('Open Redirect')

CVSS vector

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

nvd-primary

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

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

All records