Red Hat Security Advisory: OpenShift Container Platform 4.21.33 packages and security update
Affects Red HatSource GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 7.5 High · fixed in Red Hat package updates : patch Red Hat http2 soon.
Data as of 26 Oct 2026, 18:42 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 57% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.53.0, 1.26.3, 1.25.10
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 7 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 golang.org/x/net/http2 to 0.53.0; net/http to 1.26.3 or 1.25.10.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| golang.org/x/netgolang.org/x/net/http2 | Affected
| Fixed in
|
| Go standard librarynet/http | Affected
| Fixed in
|
| Go standard librarynet/http | Affected
| Fixed in
|
Gogolang.org/x/net/http2pkg:golang/golang.org/x/net/http2Other threats | Affected
| Fixed in– |
Gogolang.org/x/net/http2pkg:golang/golang.org/x/net/http2Other threats | Affected
| Fixed in
|
Gonet/httppkg:golang/net/httpOther 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
A fix is available in Red Hat OpenShift Container Platform 4.21.33 packages and images. Users are advised to upgrade to these updated packages and images through the appropriate release channel using the OpenShift CLI or web console. Detailed upgrade instructions are provided in the official Red Hat documentation. No additional mitigation actions are indicated beyond applying the update.
Description
Red Hat OpenShift Container Platform 4.21.33 includes security updates addressing multiple vulnerabilities in Go components used by the platform. These issues include denial of service via malformed HTTP/2 frames, excessive recursion in ASN.1 and XML decoding, privilege escalation through incorrect Punycode processing, directory traversal via symlink following, and denial of service from quadratic complexity in URL path resolution and indefinite TLS KeyUpdate messages. Users of OpenShift Container Platform 4.21 are advised to upgrade to the updated packages and images provided in this release.
References
- access.redhat.com/errata/RHSA-2026:66350 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2467815 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2480756 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2484204 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2498152 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2515815 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2515820 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2515839 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2515840 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_66350.json (opens in a new tab)