CVE-2025-1098: ingress-nginx Configuration Injection RCE

CVE-2025-1098 Overview

A security issue was discovered in ingress-nginx where the mirror-target and mirror-host Ingress annotations can be used to inject arbitrary 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.

Critical Impact

This vulnerability enables attackers to execute arbitrary code and access sensitive information, affecting security operations cluster-wide.

Affected Products

• ingress-nginx
• Kubernetes
• Not Available

Discovery Timeline

• Not Available - Vulnerability discovered by Not Available
• Not Available - Responsible disclosure to Not Available
• Not Available - CVE CVE-2025-1098 assigned
• Not Available - Not Available releases security patch
• 2025-03-25 - CVE CVE-2025-1098 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2025-1098

Vulnerability Analysis

The vulnerability arises from improper input validation in ingress-nginx where certain annotations can be leveraged to inject arbitrary nginx configuration. This flaw allows attackers to alter nginx behavior maliciously, potentially leading to arbitrary code execution and exposure of sensitive secrets managed by the controller.

Root Cause

The root cause of the vulnerability is the improper handling of mirror-target and mirror-host annotations, allowing an attacker to pass unintended configuration values to nginx.

Attack Vector

This is a network-based attack vector that can be exploited remotely by adversaries with minimal privileges (low access complexity).

# Example exploitation code (sanitized)
server {
    location / {
        mirror /malicious;
        mirror_request_body on;
    }
}

Detection Methods for CVE-2025-1098

Indicators of Compromise

• Unusual mirror annotations in ingress configurations
• Unexpected changes in nginx configuration files
• Unauthorized issuance of commands to access Secrets

Detection Strategies

Security teams should closely monitor ingress configurations for unconventional values and nginx configurations that go beyond the expected setup. Implement automated scripts to detect suspicious annotations that do not conform to typical ingress rules.

Monitoring Recommendations

Deploy network monitoring tools to observe ingress controller activities and log all ingress configuration changes. Regular validation of ingress annotations against a whitelist can mitigate unauthorized configurations.

How to Mitigate CVE-2025-1098

Immediate Actions Required

• Immediately review and restrict access to ingress configuration updates.
• Audit all existing ingress annotations for suspicious entries.
• Monitor network traffic for unauthorized ingress activities.

Patch Information

Not Available. Follow vendor updates via Netapp Advisory.

Workarounds

Consider implementing stricter configuration policies and using network policies to limit access to the ingress controller.

# Configuration example
kubectl annotate ingress <ingress-name> --remove="nginx.ingress.kubernetes.io/mirror-host"
kubectl annotate ingress <ingress-name> --remove="nginx.ingress.kubernetes.io/mirror-target"