CVE-2021-25740 (GCVE-0-2021-25740)
Vulnerability from cvelistv5 – Published: 2021-09-20 17:05 – Updated: 2026-06-01 21:45
VLAI
EPSS
VEX
Title
Holes in EndpointSlice Validation Enable Host Network Hijack
Summary
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.
Severity
CWE
- CWE-441 - Unintended Proxy or Intermediary
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://kubernetes.io/blog/2026/05/26/reconciling… | x_refsource_MISC |
| https://groups.google.com/g/kubernetes-security-a… | x_refsource_MISC |
| https://github.com/kubernetes/kubernetes/issues/103675 | x_refsource_MISC |
| https://security.netapp.com/advisory/ntap-2021101… | x_refsource_CONFIRM |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Kubernetes | Kubernetes |
Affected:
0 , < *
(semver)
|
guessed |
Date Public
2021-07-14 00:00
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"title": "Holes in EndpointSlice Validation Enable Host Network Hijack",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2021-25740.json",
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"nvd": {
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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Sightings and recorded dates, grouped by day · UTC
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
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