RHSA-2026:68547 - Security Advisory

Topic

Red Hat OpenShift Container Platform release 4.21.34 is now available with updates to packages and images that fix several bugs.

This release includes a security update for Red Hat OpenShift Container Platform 4.21.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

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 RPM packages for Red Hat OpenShift Container Platform 4.21.34. See the following advisory for the container images for this release:

https://access.redhat.com/errata/RHSA-2026:68546

Security Fix(es):

• fast-uri: fast-uri: Authority Injection via Unvalidated Port Serialization (CVE-2026-84292)
• fast-uri: Fast-uri: Security policy bypass due to URL parsing inconsistency (CVE-2026-16221)
• fast-uri: fast-uri: URI parsing flaw enables server-side request forgery and redirects (CVE-2026-76172)
• net/http/internal/http2: golang: golang.org/x/net: Go HTTP/2: Denial of Service via malformed SETTINGS_MAX_FRAME_SIZE frame (CVE-2026-33814)
• baseline-browser-mapping: baseline-browser-mapping: Denial of Service via improper input handling (CVE-2026-45819)
• fast-uri: fast-uri: Host confusion vulnerability via backslash in URI authority (CVE-2026-18446)
• fast-uri: fast-uri: Host confusion via unbalanced URI brackets can bypass security policies (CVE-2026-84394)
• fast-uri: fast-uri: Host confusion via skipped IDN canonicalization (CVE-2026-75931)
• fast-uri: fast-uri: Server-Side Request Forgery via repeated hostname percent-decoding (CVE-2026-75899)
• fast-uri: fast-uri: Server-side request forgery via malformed IPv6 normalization (CVE-2026-75975)

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.

Solution

See the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html/release_notes/

Details on how to access this content are available at
https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html-single/updating_clusters/index#updating-cluster-cli.

Affected Products

• Red Hat OpenShift Container Platform

Fixes

• BZ - 2467815
• BZ - 2502307
• BZ - 2509801
• BZ - 2515240
• BZ - 2521777
• BZ - 2521778
• BZ - 2521779
• BZ - 2521798
• BZ - 2527747
• BZ - 2527756

CVEs

• CVE-2026-16221
• CVE-2026-18446
• CVE-2026-33814
• CVE-2026-45819
• CVE-2026-75899
• CVE-2026-75931
• CVE-2026-75975
• CVE-2026-76172
• CVE-2026-84292
• CVE-2026-84394

References

• https://access.redhat.com/security/updates/classification/