CVE-2026-3288

High

Published: 09 March 2026

Published

09 March 2026

Modified

06 May 2026

KEV Added

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Patch

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CVSS Score 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0005 15.3th percentile

Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-3288 is a high-severity Improper Input Validation (CWE-20) vulnerability in Kubernetes Ingress-Nginx. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 15.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 AC-6 (Least Privilege) and SI-10 (Information Input Validation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190) and 2 other techniques. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match

prevent

Directly addresses CWE-20 improper input validation by requiring validation mechanisms for the rewrite-target annotation to prevent malicious configuration injection.

SI-2 Flaw Remediation good match

prevent

Ensures timely flaw remediation through patching the ingress-nginx controller vulnerability to eliminate the improper handling of the annotation.

AC-6 Least Privilege good match

prevent

Enforces least privilege to restrict low-privileged users from creating or modifying Ingress resources necessary for exploitation.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1059.004 Unix Shell Execution

Adversaries may abuse Unix shell commands and scripts for execution.

attack.mitre.org →

T1552 Unsecured Credentials Credential Access

Adversaries may search compromised systems to find and obtain insecurely stored credentials.

attack.mitre.org →

Why these techniques?

Vuln in public ingress controller enables T1190 exploitation for RCE (T1059.004 Unix shell in container) and secret disclosure (T1552).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

A security issue was discovered in ingress-nginx where the `nginx.ingress.kubernetes.io/rewrite-target` Ingress annotation can be used to inject configuration into nginx. This can lead to arbitrary code execution in the context of the ingress-nginx controller, and disclosure of Secrets accessible to…

the controller. (Note that in the default installation, the controller can access all Secrets cluster-wide.)

Deeper analysisAI

CVE-2026-3288, published on 2026-03-09, is a vulnerability in the ingress-nginx controller for Kubernetes. It stems from improper handling of the `nginx.ingress.kubernetes.io/rewrite-target` Ingress annotation, which allows attackers to inject arbitrary configuration into the underlying nginx process. This can result in arbitrary code execution within the context of the ingress-nginx controller pod, as well as disclosure of Kubernetes Secrets accessible to the controller. In default installations, the controller has cluster-wide read access to all Secrets. The issue is rated at CVSS v3.1 score 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and maps to CWE-20: Improper Input Validation.

Exploitation requires low privileges, specifically the ability to create or modify Ingress resources in a targeted namespace, and can be performed remotely over the network with low complexity and no user interaction. A successful attack grants arbitrary code execution as the ingress-nginx controller, enabling high confidentiality, integrity, and availability impacts. Attackers can also exfiltrate sensitive Secrets, potentially exposing cluster-wide credentials in default configurations.

Advisories and related resources, including the Kubernetes issue tracker (https://github.com/kubernetes/kubernetes/issues/137560), OSS-Security mailing list (http://www.openwall.com/lists/oss-security/2026/03/09/8), and a proof-of-concept lab (https://github.com/bvabhishek/CVE-2026-3288-lab), provide further details on the issue and potential mitigations.