Red Hat Security Advisory: OpenShift Container Platform 4.21.25 bug fix and security update
Red Hat OpenShift Container Platform is Red Hat's cloud computing Kubernetes application platform solution designed for on-premise or private cloud deployments. This advisory contains the container images for Red Hat OpenShift Container Platform 4.21.25. See the following advisory for the RPM packages for this release: https://access.redhat.com/errata/RHBA-2026:40778 Space precludes documenting all of the container images in this advisory. See the following Release Notes documentation, which will be updated shortly for this release, for details about these changes: https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html/release_notes/ Security Fix(es): * kernel: eventpoll: fix ep_remove struct eventpoll / struct file UAF (CVE-2026-46242) * kernel: KVM: arm64: vgic-its: Drop the translation cache reference only for the erased entry (CVE-2026-46316) * kernel: KVM: x86: Fix shadow paging use-after-free due to unexpected role (CVE-2026-53359) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section. All OpenShift Container Platform 4.21 users are advised to upgrade to these updated packages and images when they are available in the appropriate release channel. To check for available updates, use the OpenShift CLI (oc) or web console. Instructions for upgrading a cluster are available at https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html-single/updating_clusters/index#updating-cluster-cli.
AI Analysis
Technical Summary
CVE-2026-46242 is a use-after-free vulnerability in the Linux kernel eventpoll subsystem. The ep_remove() function cleared the file->f_ep pointer under lock but continued to use the file pointer inside the critical section, leading to a race condition with concurrent __fput() calls that could free the watched struct eventpoll prematurely. This results in hlist_del_rcu() operating on freed memory and potential corruption of slab caches due to recycling of struct file objects. The fix involves pinning the file structure at the start of ep_remove() to prevent it from reaching zero refcount and being freed during the critical section, thus preventing the UAF conditions.
Potential Impact
Successful exploitation could lead to use-after-free conditions causing memory corruption in the kernel, which may result in privilege escalation, denial of service, or arbitrary code execution within the kernel context. The vulnerability affects confidentiality, integrity, and availability of the system.
Mitigation Recommendations
A fix is available in Linux kernel version 6.18.33. Users should upgrade to version 6.18.33 or later to remediate this vulnerability. No additional mitigations are indicated beyond applying the official patch.
Red Hat Security Advisory: OpenShift Container Platform 4.21.25 bug fix and security update
Description
Red Hat OpenShift Container Platform is Red Hat's cloud computing Kubernetes application platform solution designed for on-premise or private cloud deployments. This advisory contains the container images for Red Hat OpenShift Container Platform 4.21.25. See the following advisory for the RPM packages for this release: https://access.redhat.com/errata/RHBA-2026:40778 Space precludes documenting all of the container images in this advisory. See the following Release Notes documentation, which will be updated shortly for this release, for details about these changes: https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html/release_notes/ Security Fix(es): * kernel: eventpoll: fix ep_remove struct eventpoll / struct file UAF (CVE-2026-46242) * kernel: KVM: arm64: vgic-its: Drop the translation cache reference only for the erased entry (CVE-2026-46316) * kernel: KVM: x86: Fix shadow paging use-after-free due to unexpected role (CVE-2026-53359) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section. All OpenShift Container Platform 4.21 users are advised to upgrade to these updated packages and images when they are available in the appropriate release channel. To check for available updates, use the OpenShift CLI (oc) or web console. Instructions for upgrading a cluster are available at https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html-single/updating_clusters/index#updating-cluster-cli.
CVSS v3.1
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-46242 is a use-after-free vulnerability in the Linux kernel eventpoll subsystem. The ep_remove() function cleared the file->f_ep pointer under lock but continued to use the file pointer inside the critical section, leading to a race condition with concurrent __fput() calls that could free the watched struct eventpoll prematurely. This results in hlist_del_rcu() operating on freed memory and potential corruption of slab caches due to recycling of struct file objects. The fix involves pinning the file structure at the start of ep_remove() to prevent it from reaching zero refcount and being freed during the critical section, thus preventing the UAF conditions.
Potential Impact
Successful exploitation could lead to use-after-free conditions causing memory corruption in the kernel, which may result in privilege escalation, denial of service, or arbitrary code execution within the kernel context. The vulnerability affects confidentiality, integrity, and availability of the system.
Mitigation Recommendations
A fix is available in Linux kernel version 6.18.33. Users should upgrade to version 6.18.33 or later to remediate this vulnerability. No additional mitigations are indicated beyond applying the official patch.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_vex
- Csaf Version
- 2.0
- Publisher
- Microsoft Security Response Center
- Advisory Id
- msrc_CVE-2026-46242
- Cve Count
- 1
- Additional Cves
- []
- Cvss Version
- null
Threat ID: 6a1ca158e29bf47b505e1f5f
Added to database: 05/31/2026, 21:00:08 UTC
Last enriched: 07/04/2026, 23:23:52 UTC
Last updated: 07/21/2026, 20:57:08 UTC
Views: 140
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