Red Hat Security Advisory: OpenShift Container Platform 4.21.23 bug fix and security update
Affects Red HatSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 7.5 High : upgrade Red Hat to 3.8.13 soon.
Data as of 26 Oct 2026, 18:43 UTC
- Patch
- Available – fixed in 3.8.13
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 18 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade gnutls to 3.8.13.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| gnutls | Affected
| Fixed in
|
AI-suggested
Users of Red Hat OpenShift Container Platform 4.21 should upgrade to version 4.21.23, which contains the updated container images and packages that address these vulnerabilities. The update is available through the appropriate release channels and can be applied using the OpenShift CLI (oc) or the web console. Detailed upgrade instructions are provided in the official Red Hat documentation. No alternative mitigations or workarounds are specified, so applying the update is the recommended action.
Description
Red Hat OpenShift Container Platform 4.21.23 includes important security updates addressing three vulnerabilities: a denial of service via DTLS packet reordering in gnutls (CVE-2026-42009), an authentication bypass via a NUL character in username in gnutls (CVE-2026-42010), and a Linux kernel SMB client issue rejecting userspace cifs.spnego descriptions (CVE-2026-46243). Users of OpenShift Container Platform 4.21 are advised to upgrade to the updated packages and container images available through the appropriate release channels.
References
- access.redhat.com/errata/RHSA-2026:34764 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2467279 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2467289 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2481486 (opens in a new tab)
- issues.redhat.com/browse/OCPBUGS-88740 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_34764.json (opens in a new tab)