CVE-2021-25736 Vulnerability Analysis & Exploit Details

CVE-2021-25736
Vulnerability Scoring

5.8
/10
Significant Risk

Security assessments indicate that CVE-2021-25736 presents a notable risk, potentially requiring prompt mitigation.

Attack Complexity Details

  • Attack Complexity: High
    Exploits require significant effort and special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: High
    High-level privileges are required for exploitation.
  • Scope: Changed
    Successful exploitation can impact components beyond the vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2021-25736 Details

Status: Modified

Last updated: 🕒 12 Jun 2025, 15:15 UTC
Originally published on: 🕒 30 Oct 2023, 03:15 UTC

Time between publication and last update: 591 days

CVSS Release: version 3

CVSS3 Source

jordan@liggitt.net

CVSS3 Type

Secondary

CVSS3 Vector

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

CVE-2021-25736 Vulnerability Summary

CVE-2021-25736: 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.

Assessing the Risk of CVE-2021-25736

Access Complexity Graph

The exploitability of CVE-2021-25736 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2021-25736

The exploitability of CVE-2021-25736 is influenced by multiple factors. Security teams should analyze system configurations and apply appropriate countermeasures to mitigate threats.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2021-25736, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2021-25736, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: High
    Exploiting CVE-2021-25736 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: None
    CVE-2021-25736 poses no threat to data integrity.
  • Availability: None
    CVE-2021-25736 does not impact system availability.

Exploit Prediction Scoring System (EPSS)

The EPSS score estimates the probability that this vulnerability will be exploited in the near future.

EPSS Score: 0.122% (probability of exploit)

EPSS Percentile: 48.11% (lower percentile = lower relative risk)
This vulnerability is less risky than approximately 51.89% of others.

CVE-2021-25736 References

External References

CWE Common Weakness Enumeration

CWE-114

CAPEC Common Attack Pattern Enumeration and Classification

  • Command Line Execution through SQL Injection CAPEC-108 An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.
  • Inclusion of Code in Existing Process CAPEC-640 The adversary takes advantage of a bug in an application failing to verify the integrity of the running process to execute arbitrary code in the address space of a separate live process. The adversary could use running code in the context of another process to try to access process's memory, system/network resources, etc. The goal of this attack is to evade detection defenses and escalate privileges by masking the malicious code under an existing legitimate process. Examples of approaches include but not limited to: dynamic-link library (DLL) injection, portable executable injection, thread execution hijacking, ptrace system calls, VDSO hijacking, function hooking, reflective code loading, and more.

Vulnerable Configurations

  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:rc1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:rc1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:beta0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:beta0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:beta1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:beta1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:beta2:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:beta2:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha2:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha2:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha3:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha3:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha4:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha4:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha5:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.0:alpha5:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.1:beta0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.1:beta0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.2:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.2:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.2:beta0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.2:beta0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.3:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.3:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.3:beta0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.3:beta0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.4:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.4:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.4:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.4:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.5:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.5:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.5:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.5:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.5:rc1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.5:rc1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.6:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.6:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.6:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.6:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.7:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.7:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.7:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.7:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.8:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.8:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.8:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.8:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.8:rc1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.8:rc1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.9:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.9:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.9:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.9:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.10:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.10:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.10:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.10:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.18.17:*:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.18.17:*:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:rc1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:rc1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:rc2:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:rc2:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:rc3:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:rc3:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:rc4:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:rc4:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:beta0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:beta0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:beta1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:beta1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:beta2:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:beta2:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:alpha0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:alpha0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:alpha1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:alpha1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:alpha2:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:alpha2:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.0:alpha3:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.0:alpha3:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.1:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.1:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.1:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.1:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.2:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.2:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.2:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.2:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.3:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.3:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.3:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.3:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.4:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.4:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.4:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.4:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.5:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.5:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.5:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.5:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.6:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.6:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.6:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.6:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.6:rc1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.6:rc1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.7:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.7:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.7:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.7:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.8:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.8:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.8:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.8:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.9:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.9:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.19.9:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.19.9:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.0:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.0:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.0:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.0:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.0:beta0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.0:beta0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.0:beta1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.0:beta1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.0:beta2:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.0:beta2:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.0:alpha0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.0:alpha0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.0:alpha1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.0:alpha1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.0:alpha2:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.0:alpha2:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.0:alpha3:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.0:alpha3:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.1:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.1:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.1:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.1:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.1:rc1:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.1:rc1:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.2:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.2:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.2:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.2:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.3:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.3:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.3:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.3:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.4:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.4:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.4:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.4:rc0:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.5:-:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.5:-:*:*:*:*:*:*
  • cpe:2.3:a:kubernetes:kubernetes:1.20.5:rc0:*:*:*:*:*:*
    cpe:2.3:a:kubernetes:kubernetes:1.20.5:rc0:*:*:*:*:*:*
  • cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*
    cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*

Protect Your Infrastructure against CVE-2021-25736: Combat Critical CVE Threats

Stay updated with real-time CVE vulnerabilities and take action to secure your systems. Enhance your cybersecurity posture with the latest threat intelligence and mitigation techniques. Develop the skills necessary to defend against CVEs and secure critical infrastructures. Join the top cybersecurity professionals safeguarding today's infrastructures.

Other 5 Recently Published CVEs Vulnerabilities

  • CVE-2025-5072 – Resource leak vulnerability in ASR180x、ASR190x in con_mgr allows Resource Leak Exposure.This issue affects Falcon_Linux、Kestrel、Lapwing_Linux: befo...
  • CVE-2025-41656 – An unauthenticated remote attacker can run arbitrary commands on the affected devices with high privileges because the authentication for the Node_...
  • CVE-2025-41648 – An unauthenticated remote attacker can bypass the login to the web application of the affected devices making it possible to access and change all ...
  • CVE-2025-6934 – The Opal Estate Pro – Property Management and Submission plugin for WordPress, used by the FullHouse - Real Estate Responsive WordPress Theme, is v...
  • CVE-2025-6081 – Insufficiently Protected Credentials in LDAP in Konica Minolta bizhub 227 Multifunction printers version GCQ-Y3 or earlier allows an attacker can r...