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NVD / CVE Program· CNA kubernetes

CVE-2020-8562: Bypass of Kubernetes API Server proxy TOCTOU

Noroxi assessment

Priority: Monitor (action score 12/100)

  • 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: 1.1% (FIRST EPSS); higher than 67.7% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: kubernetes (Debian:12) 1.20.5+really1.20.2-1; govulncheck-vulndb (openSUSE:Tumbleweed) 0.0.20250807T150727-1.1.

Low priority for now. Upgrade to kubernetes (Debian:12) 1.20.5+really1.20.2-1; govulncheck-vulndb (openSUSE:Tumbleweed) 0.0.20250807T150727-1.1 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

As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction and access private networks on the control plane.

LowCVSS 3.1 · v3.1—No exploit Fix available
Published
Feb 1, 2022
Updated
Jun 16, 2026
EPSS
1.1% · 67th percentile

Report tools

JSON

Action score

12

Monitor

Low priority for now.

CVSS
12 / 40 · 3.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.1%

CNA vs NVD score

NVD
3.1
CNA · kubernetes
2.2
0.9 point gap

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

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

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  • 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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When you'll hear from us

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  • 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?

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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
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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 kubernetesup to 1.18.18 inclusive
  • kubernetes kubernetes1.19.0 and later · up to 1.19.10 inclusive
  • kubernetes kubernetes1.20.0 and later · up to 1.20.6 inclusive
  • kubernetes kubernetes1.21.0

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

    • all versionsaffected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12kubernetesbefore 1.20.5+really1.20.2-11.20.5+really1.20.2-1
Gok8s.io/kubernetesfrom 1.19.0 · up to and including 1.19.11—
Gok8s.io/kubernetesfrom 1.20.0 · up to and including 1.20.7—
Gok8s.io/kubernetesfrom 1.21.0 · up to and including 1.21.1—
Gok8s.io/kubernetesup to and including 1.18.19—
openSUSE:Tumbleweedgovulncheck-vulndbbefore 0.0.20250807T150727-1.10.0.20250807T150727-1.1

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-2021-25741Sep 20, 2021 · Symlink Exchange Can Allow Host Filesystem Access
    34Monitor
  • ← EarlierCVE-2021-25743Jan 6, 2022 · ANSI escape characters in kubectl output are not being filtered
    12Monitor
  • Later →CVE-2022-3162Mar 1, 2023 · Unauthorized read of Custom Resources
    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:kubernetes1.20.5+really1.20.2-1 · Debian:12Package registry (OSV)
opensuse:govulncheck-vulndb0.0.20250807T150727-1.1 · openSUSE:TumbleweedPackage 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
low · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition

CVSS vector

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

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✗ → ✓

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References

Show all references (3 more)

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

All records