CVE-2021-25736

MEDIUMNVD 5.85.8—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.8 under NVD CVSS v3. EPSS exploit probability: 0.9%, top 44% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
5.8
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 5.8Exploit: NoneExposed: 0

A fix is available — apply it.

Kube-proxy on Windows can unintentionally forward traffic to local processes listening on the same port (“spec.ports[*].port”) as a LoadBalancer Service when the LoadBalancer controller does not set the “status.loadBalancer.ingress[].ip” field. Clusters where the LoadBalancer controller sets the “status.loadBalancer.ingress[].ip” field are unaffected.

CVSS v3
5.8
EG Score
5.8(medium)
EG Risk
—
EPSS
56.4%
KEV
Not listed

Published

October 30, 2023

Last Modified

June 12, 2025

References (6)

Vendor Advisories for CVE-2021-25736(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatopenshift4-wincw/windows-machine-config-rhel8-operator:2.0.1-62021-06-23redhat

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)
PackageVulnerable rangeFixed inDependents
k8s.io/kubernetes—1.21.0—

Weakness Classification(1)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 12× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-22 22:45 UTCEG score recompute
  2. 2026-07-22 14:06 UTCEPSS rescore
  3. 2026-07-22 14:06 UTCEPSS rescore
  4. 2026-07-21 15:22 UTCEPSS rescore
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  12. 2026-07-16 17:00 UTCEPSS rescore
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  14. 2026-07-15 16:55 UTCEPSS rescore
  15. 2026-07-15 05:49 UTCOSV refresh
  16. 2026-07-15 01:58 UTCEPSS rescore
  17. 2026-07-13 22:27 UTCEPSS rescore
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  19. 2026-07-13 06:10 UTCEPSS rescore
  20. 2026-07-12 05:44 UTCEPSS rescore
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  22. 2026-07-11 08:25 UTCEPSS rescore
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  24. 2026-07-09 19:07 UTCEPSS rescore
  25. 2026-07-08 15:12 UTCEPSS rescore
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  1. 2026-07-07 13:43 UTCEPSS rescore
  2. 2026-07-06 16:25 UTCEPSS rescore
  3. 2026-07-06 16:25 UTCEPSS rescore
  4. 2026-07-06 02:21 UTCEPSS rescore
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  6. 2026-07-05 02:28 UTCEPSS rescore
  7. 2026-07-04 06:29 UTCEPSS rescore
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  9. 2026-07-02 16:57 UTCEPSS rescore
  10. 2026-07-01 15:03 UTCEPSS rescore
  11. 2026-06-30 23:20 UTCEPSS rescore
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  13. 2026-06-29 14:04 UTCEPSS rescore
  14. 2026-06-28 04:54 UTCEPSS rescore
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  16. 2026-06-27 06:04 UTCOSV refresh
  17. 2026-06-27 03:06 UTCEPSS rescore
  18. 2026-06-27 03:06 UTCEPSS rescore
  19. 2026-06-25 13:48 UTCEPSS rescore
  20. 2026-06-25 13:48 UTCEPSS rescore
  21. 2026-06-24 14:03 UTCEPSS rescore
  22. 2026-06-24 14:03 UTCEPSS rescore
  23. 2026-06-23 21:31 UTCEPSS rescore
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  25. 2026-06-22 14:24 UTCEPSS rescore
  26. 2026-06-22 14:24 UTCEPSS rescore
  27. 2026-06-21 14:55 UTCEPSS rescore
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  29. 2026-06-21 01:58 UTCEPSS rescore
  30. 2026-06-21 01:58 UTCEPSS rescore
  31. 2026-06-19 19:24 UTCEPSS rescore
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  33. 2026-06-18 17:51 UTCEPSS rescore
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  35. 2026-06-17 17:51 UTCEPSS rescore
  36. 2026-06-16 17:51 UTCEPSS rescore
  37. 2026-06-15 17:46 UTCEPSS rescore
  38. 2026-06-14 23:15 UTCEPSS rescore
  39. 2026-06-13 22:58 UTCEPSS rescore
  40. 2026-06-13 22:58 UTCEPSS rescore
  41. 2026-06-12 23:10 UTCEPSS rescore
  42. 2026-06-11 13:58 UTCEPSS rescore
  43. 2026-06-10 22:16 UTCEPSS rescore
  44. 2026-06-10 13:20 UTCEPSS rescore
  45. 2026-06-09 16:47 UTCOSV refresh
  46. 2026-06-08 14:15 UTCEPSS rescore
  47. 2026-06-07 15:23 UTCEPSS rescore
  48. 2026-06-07 15:23 UTCEPSS rescore
  49. 2026-06-06 13:46 UTCEPSS rescore
  50. 2026-06-06 13:46 UTCEPSS rescore
  51. 2026-06-06 13:46 UTCEPSS rescore
  52. 2026-06-05 22:45 UTCEPSS rescore
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  54. 2026-06-05 06:09 UTCEPSS rescore
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  56. 2026-06-04 13:10 UTCEPSS rescore
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  58. 2026-06-02 20:11 UTCEPSS rescore
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  60. 2026-06-02 20:11 UTCEPSS rescore
  61. 2026-06-01 13:50 UTCEPSS rescore
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  63. 2026-05-31 22:29 UTCEPSS rescore
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  65. 2026-05-31 00:15 UTCEPSS rescore
  66. 2026-05-29 13:42 UTCEPSS rescore
  67. 2026-05-28 13:43 UTCEPSS rescore
  68. 2026-05-28 13:43 UTCEPSS rescore
  69. 2026-05-27 13:39 UTCEPSS rescore
  70. 2026-05-27 13:39 UTCEPSS rescore
  71. 2026-05-26 13:42 UTCEPSS rescore
  72. 2026-05-26 07:17 UTCEPSS rescore
  73. 2026-05-26 07:17 UTCEPSS rescore
  74. 2026-05-24 14:54 UTCEG score recompute
  75. 2026-05-24 14:54 UTCVendor advisory

Frequently asked(5)

What is CVE-2021-25736?
CVE-2021-25736 is a medium vulnerability published on October 30, 2023. Kube-proxy on Windows can unintentionally forward traffic to local processes listening on the same port (“spec.ports[*].port”) as a LoadBalancer Service when the LoadBalancer controller does not set the “status.loadBalancer.ingress[].ip” field. Clusters where the LoadBalancer controller sets the…
When was CVE-2021-25736 disclosed?
CVE-2021-25736 was first published in the National Vulnerability Database on October 30, 2023, with the most recent update on June 12, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-25736 actively exploited?
CVE-2021-25736 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 56.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-25736?
CVE-2021-25736 has a CVSS v3 base score of 5.8 (NVD).
How do I remediate CVE-2021-25736?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-25736, 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.

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