// For flags

CVE-2021-25736

Windows kube-proxy LoadBalancer contention

Severity Score

6.3
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

Kube-proxy en Windows puede reenviar tráfico involuntariamente a procesos locales que escuchan en el mismo puerto (“spec.ports[*].port”) que LoadBalancer Service cuando el controlador LoadBalancer no configura “status.loadBalancer.ingress[].ip”. Los clústeres donde el controlador LoadBalancer establece el campo "status.loadBalancer.ingress[].ip" no se ven afectados.

A flaw was found in the Windows kube-proxy component. In a cloud environment that does not set the “.status.loadBalancer.ingress.ip” field in the LoadBalancer service status configuration (for example in AWS) the packets can be misrouted and reach an unintended destination.

*Credits: Eric Paris , Christian Hernandez
CVSS Scores
Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Network
Attack Complexity
High
Privileges Required
High
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-01-21 CVE Reserved
  • 2021-06-23 CVE Published
  • 2023-12-22 EPSS Updated
  • 2024-08-03 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Kubernetes
Search vendor "Kubernetes"
Kubernetes
Search vendor "Kubernetes" for product "Kubernetes"
>= 1.18.0 < 1.18.18
Search vendor "Kubernetes" for product "Kubernetes" and version " >= 1.18.0 < 1.18.18"
-
Affected
in Microsoft
Search vendor "Microsoft"
Windows
Search vendor "Microsoft" for product "Windows"
--
Safe
Kubernetes
Search vendor "Kubernetes"
Kubernetes
Search vendor "Kubernetes" for product "Kubernetes"
>= 1.19.0 < 1.19.10
Search vendor "Kubernetes" for product "Kubernetes" and version " >= 1.19.0 < 1.19.10"
-
Affected
in Microsoft
Search vendor "Microsoft"
Windows
Search vendor "Microsoft" for product "Windows"
--
Safe
Kubernetes
Search vendor "Kubernetes"
Kubernetes
Search vendor "Kubernetes" for product "Kubernetes"
>= 1.20.0 < 1.20.6
Search vendor "Kubernetes" for product "Kubernetes" and version " >= 1.20.0 < 1.20.6"
-
Affected
in Microsoft
Search vendor "Microsoft"
Windows
Search vendor "Microsoft" for product "Windows"
--
Safe