CVE-2021-25740

LOWNVD 3.13.1—

3.1

A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.

CVSS v3: 3.1
EG Score: 3.1(medium)
EPSS: 66.4%
KEV: Not listed

Published

September 20, 2021

Last Modified

November 21, 2024

References (6)

jordan@liggitthttps://github.com/kubernetes/kubernetes/issues/103675
jordan@liggitthttps://groups.google.com/g/kubernetes-security-announce/c/WYE9ptrhSLE
jordan@liggitthttps://security.netapp.com/advisory/ntap-20211014-0001/
af854a3a-2127-422b-91ae-364da2661108https://github.com/kubernetes/kubernetes/issues/103675
af854a3a-2127-422b-91ae-364da2661108https://groups.google.com/g/kubernetes-security-announce/c/WYE9ptrhSLE
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20211014-0001/

Patch Availability(1)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
go	k8s.io/kubernetes	—	ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)

Go(1)

Package	Vulnerable range	Fixed in	Dependents
k8s.io/kubernetes	—	—	—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 7× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 10:06 UTCEG score recompute
2026-05-26 10:06 UTCGHSA enrichment
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2021-25740?

CVE-2021-25740 is a low vulnerability published on September 20, 2021. A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.

When was CVE-2021-25740 disclosed?

CVE-2021-25740 was first published in the National Vulnerability Database on September 20, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-25740 actively exploited?

CVE-2021-25740 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 66.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-25740?

CVE-2021-25740 has a CVSS v3 base score of 3.1 (NVD).

How do I remediate CVE-2021-25740?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-25740, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-25740

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