Red Hat Security Advisory: OpenShift Container Platform 4.21.28 bug fix and security update
Affects Red HatSource GCVE Database
Not known to be exploited · CVSS 8.5 High · fixed in Red Hat OpenShift Container Platform 4.12 package updates : patch Red Hat soon.
Data as of 10 Nov 2026, 23:24 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 45% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.21.28
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 28 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 11 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red HatRed Hat OpenShift Container Platform 4.12 | Affected– | Fixed in– |
| Red HatRed Hat OpenShift Container Platform 4.13 | Affected– | Fixed in– |
| Red HatRed Hat OpenShift Container Platform 4.14 | Affected– | Fixed in– |
| Red HatRed Hat OpenShift Container Platform 4.15 | Affected– | Fixed in– |
| Red HatRed Hat OpenShift Container Platform 4.16 | Affected– | Fixed in– |
| Red HatRed Hat OpenShift Container Platform 4.17 | Affected– | Fixed in– |
AI-suggested
Red Hat has released OpenShift Container Platform 4.21.28 containing fixes for this vulnerability. Users should upgrade to version 4.21.28 or later to fully remediate the issue. Additionally, upstream applications should implement hardening by validating the X-Forwarded-User header against the expected session identity and rejecting requests where identity headers do not match the authenticated session. No other vendor advisories indicate alternative mitigations or that no action is required.
Description
A vulnerability in Red Hat OpenShift Container Platform's oauth-proxy component allows an authenticated low-privilege user to impersonate another identity by exploiting header normalization differences in WSGI and PHP frameworks. The proxy sets authenticated identity headers using dash-variant keys but does not remove underscore-variant keys, which are normalized to the same variable upstream. This can lead to identity smuggling and potential impersonation. Red Hat has released OpenShift Container Platform 4.21.28 with fixes addressing this issue.
References
- access.redhat.com/errata/RHSA-2026:51025 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-49332 (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_51025.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:50681 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:50758 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:51007 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:51013 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:51022 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:51038 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2483253 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:54206 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:54188 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:56912 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:60023 (opens in a new tab)