Security Bulletin
Summary
IBM Cloud Kubernetes Service is affected by Kubernetes Ingress Controller security vulnerabilities where a user that can create or update Ingress objects can use the nginx.ingress.kubernetes.io/auth-url annotation (CVE-2025-24514) or the nginx.ingress.kubernetes.io/auth-tls-match-cn annotation (CVE-2025-1097) or nginx.ingress.kubernetes.io/mirror-target and nginx.ingress.kubernetes.io/mirror-host annotations (CVE-2025-1098) to inject arbitrary configuration to obtain the credentials of the Kubernetes Ingress Controller (ALB). In the default configuration, that credential has access to all secrets in the cluster.
These vulnerabilities are relevant mainly in multi-tenant environments where non-admin users have permissions to create Ingress objects.
Note: IBM Cloud Kubernetes Service is not affected by Kubernetes Ingress Controller security vulnerabilities related to the Validating Admission Controller functionality of ingress-nginx (CVE-2025-1974 and CVE-2025-24513), as IBM Cloud Kubernetes Service team disabled the Ingress Validation Webhook feature on all managed Ingress Controller.
Vulnerability Details
A security issue was discovered in ingress-nginx https://github.com/kubernetes/ingress-nginx where the
auth-url 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.)CWE: CWE-20
CVSS Source: https://github.com/kubernetes/kubernetes/issues/131006
CVSS Base Score: 8.8
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
A security issue was discovered in ingress-nginx https://github.com/kubernetes/ingress-nginx where the
auth-tls-match-cn 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.)CWE: CWE-20
CVSS Source: https://github.com/kubernetes/kubernetes/issues/131007
CVSS Base Score: 8.8
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
A security issue was discovered in ingress-nginx https://github.com/kubernetes/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.)CWE: CWE-20
CVSS Source: https://github.com/kubernetes/kubernetes/issues/131008
CVSS Base Score: 8.8
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected Products and Versions
1.12.1_7490_iksRemediation/Fixes
New Kubernetes Ingress Controller (ALB) versions 1.12.1_7490_iks contains fixes for these vulnerabilities and is available immediately for early adopters. To update your ALBs before the automatic update period for this version you will need to disable automatic updates and apply the version manually. The fixed version will be automatically applied to all clusters once it has passed all GA validation and is marked as the default version for ALBs.
Optionally, for additional security you can disable certain annotations by lowering the annotation risk level in the ALB ConfigMap (kube-system / ibm-k8s-controller-config). The default risk level is currently set to Critical which can be lowered to High, Medium or Low. Consult the ingress-nginx documentation to see the risk levels for annotations.
Action Required
Update Kubernetes Ingress Controllers (ALBs) to version 1.12.1_7490_iks or later.
- Review the annotations on your Ingress resources and make sure that the configuration values are valid.
- Disable automatic updates by running the
ibmcloud ks ingress alb autoupdate disablecommand. This prevents downgrading your ALBs to the default version currently1.11.2 - Update your ALBs to the new version by running the
ibmcloud ks ingress alb update --version 1.12.1_7490_ikscommand.
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References
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.
Document Location
Worldwide
Product Synonym
IKS
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Document Information
Modified date:
03 April 2025
UID
ibm17230036