Openshift/oauth-proxy: openshift/oauth-proxy: underscore header smuggling enables identity impersonation on wsgi/php upstreams

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-49332
StatePUBLISHED
Assignerredhat
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-28 13:18:46 UTC
Updated2026-07-28 16:22:01 UTC
DescriptionA flaw was found in openshift/oauth-proxy. The proxy sets authenticated identity headers using only dash-variant keys (X-Forwarded-User) but does not strip underscore-variant keys (X_Forwarded_User) from incoming requests. WSGI and PHP frameworks normalize both variants to the same variable, allowing an authenticated low-privilege user to smuggle a forged identity that may override the legitimate authenticated identity in the upstream application.

Risk And Classification

Primary CVSS: v3.1 8.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

EPSS: 0.001940000 probability, percentile 0.093770000 (date 2026-07-29)

Problem Types: CWE-436 | CWE-436 Interpretation Conflict

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary8.5HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
3.1CNACVSS8.5HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Red Hat Red Hat OpenShift Container Platform 4 Not specified Not specified
CNA Red Hat Red Hat OpenShift Container Platform 4 Not specified Not specified

References

ReferenceSourceLinkTags
bugzilla.redhat.com/show_bug.cgi [email protected] bugzilla.redhat.com
access.redhat.com/security/cve/CVE-2026-49332 [email protected] access.redhat.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: This issue was discovered by Jeremy Choi (Red Hat). (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-04-17T00:00:00.000ZReported to Red Hat.
CNA2026-07-28T12:00:00.000ZMade public.

Workarounds

CNA: Upstream application hardening: validate X-Forwarded-User against the expected session identity. Reject requests where identity headers do not match the authenticated session.

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