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

Exp

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.

Published: 2020-07-22 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-8559 is rated High Exploit Risk (73/100): CVSS Medium severity, with high exploitation likelihood (EPSS 51.20%, 98th percentile). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2020-8559

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2020-8559

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-23 53.01% 51.20% -1.80%
2 2026-03-21 51.20% 53.01% +1.80%
3 2026-03-04 — 51.20% —

Full EPSS history (46 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-8559

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 0.5 5.9 [email protected]
6.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 0.9 5.9 [email protected]
6.0 2.0 MEDIUM
AV:N/AC:M/Au:S/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 6.8 6.4 [email protected]

Weakness enumeration for CVE-2020-8559

GitHub Security Advisory for CVE-2020-8559

GHSA-33c5-9fx5-fvjm · Severity: medium · Ecosystem: go — Privilege Escalation in Kubernetes

OS Trackers for CVE-2020-8559

vendor priority summary link
alpine medium CVE-2020-8559: 1 source package rows (k3s); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2020-8559
debian not yet assigned CVE-2020-8559 not yet assigned priority: Debian including 1 source packages (kubernetes), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-8559
redhat medium — https://access.redhat.com/security/cve/CVE-2020-8559
suse medium CVE-2020-8559 severity moderate: SUSE including 5 source package names (kubernetes, kubernetes-client, kubernetes-common, kubernetes-kubeadm, kubernetes-kubelet), 21 product×package rows across 8 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (8 product lines)): Known Not Affected 21. https://www.suse.com/security/cve/CVE-2020-8559/
ubuntu medium CVE-2020-8559 medium priority: Ubuntu including 1 source packages (kubernetes), 16 status rows across 16 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): ignored 8, DNE 4, not-affected 3, needs-triage 1. https://ubuntu.com/security/CVE-2020-8559

Affected software / configurations for CVE-2020-8559

Vendor Product Version Raw CPE
kubernetes kubernetes >= 1.6.0, <= 1.15.0 cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*
kubernetes kubernetes >= 1.16.0, < 1.16.13 cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*
kubernetes kubernetes >= 1.17.0, < 1.17.9 cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*
kubernetes kubernetes >= 1.18.0, < 1.18.6 cpe:2.3:a:kubernetes:kubernetes:*:*:*:*:*:*:*:*

References for CVE-2020-8559

cvelogic Threat Intelligence