Security Bulletin
Summary
IBM Cloud Kubernetes Service is affected by Kubernetes Ingress Controller security vulnerability (CVE-2026-3288).
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.)
All IKS versions with managed ALBs enabled on the cluster are impacted.
Vulnerability Details
CVEID: CVE-2026-3288
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.
CWE: CWE-20
CVSS Source: https://github.com/kubernetes/kubernetes/issues/137560
CVSS Base Score: 8.8 High
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
IBM Cloud Kubernetes Service clusters with Kubernetes Ingress Controllers (ALB) with versions below 1.12.1_321693951_iks, 1.13.7_321693992_iks build versions.
Workarounds and Mitigations
Action Required
No action required if automatic updates for the Kubernetes Ingress Controllers (ALBs) are enabled.
To check whether automatic updates for the Kubernetes Ingress Controllers (ALBs) are enabled, run ibmcloud ks ingress alb autoupdate get
If automatic updates are disabled, manually update to one of the supported Kubernetes Ingress Controller (ALB) versions.
ibmcloud ks ingress alb update --version 1.12.1_322295655_iks
To see supported Kubernetes Ingress Controller (ALB) versions, run: ibmcloud ks ingress alb versions
Kubernetes Ingress versions
1.12.1_322295655_iks (default)
1.13.7_322286017_iks
To see Kubernetes Ingress Controller (ALB) versions running in the cluster, run: ibmcloud ks ingress alb ls
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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; ROKS;
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Document Information
Modified date:
11 March 2026
UID
ibm17263199