Red Hat Security Advisory: OpenShift Container Platform 4.21.26 security and extras update
Affects Red HatSource GCVE Database
Mentioned vulnerabilities
Public exploit available · CVSS 7.7 High.
Data as of 30 Oct 2026, 11:34 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/S:N/AU:Y/R:U/V:D/RE:M/U:AmberExploitation evidence
Disclosed: evidence found.
CVE published 30 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
CVSS exploit maturity: proof of concept public
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), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 24 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| juliangruberbrace-expansion | Affected
| Fixed in– |
npmbrace-expansionpkg:npm/brace-expansionOther threats | Affected
| Fixed in– |
npmbrace-expansionpkg:npm/brace-expansionOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Red Hat has released fixed RPM packages and container images in OpenShift Container Platform 4.21.26 to address these vulnerabilities. Users should upgrade to these updated packages and images through the appropriate release channels using the OpenShift CLI or web console. Detailed upgrade instructions are available in Red Hat's official documentation. Applying these updates fully mitigates the identified security issues.
Description
Red Hat OpenShift Container Platform 4.21.26 includes security updates addressing two vulnerabilities: a security policy bypass due to improper Unicode hostname canonicalization (CVE-2026-13676) and a denial of service caused by exponential-time complexity in brace-expansion (CVE-2026-13149). These issues have been rated as important by Red Hat Product Security. Users of OpenShift Container Platform 4.21 are advised to upgrade to the updated packages and images to mitigate these vulnerabilities.
References
- access.redhat.com/errata/RHSA-2026:44268 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-13149 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-13676 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_44268.json (opens in a new tab)