CVE-2026-49329
Openshift/oauth-server: openshift/oauth-server: quadratic-time dos via accept-language header underscore bypass on unauthenticated login endpoints
CVSS Score
7.5
EPSS Score
0.8%
EPSS Percentile
57th
A flaw was found in openshift/oauth-server. The OAuth login and error page endpoints pass the unauthenticated Accept-Language header to golang.org/x/text/language.ParseAcceptLanguage() without input validation. A bypass of the CVE-2022-32149 mitigation exists: the upstream guard counts only '-' characters but the internal BCP 47 scanner aliases '_' to '-' after the guard check. An unauthenticated attacker can send a crafted Accept-Language header using '_' separators to trigger quadratic-time parsing, consuming excessive CPU and denying authentication to all cluster users.
| CWE | CWE-407 |
| Vendor | red hat |
| Product | red hat openshift container platform 4.18 |
| Published | Sep 1, 2026 |
| Last Updated | Oct 15, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
Red Hat / Red Hat OpenShift Container Platform 4.18
All versions affected Red Hat / Red Hat OpenShift Container Platform 4.19
All versions affected Red Hat / Red Hat OpenShift Container Platform 4.20
All versions affected Red Hat / Red Hat OpenShift Container Platform 4.21
All versions affected Red Hat / Red Hat OpenShift Container Platform 4.22
All versions affected Red Hat / Red Hat OpenShift Container Platform 4
All versions affected References
access.redhat.com: https://access.redhat.com/errata/RHSA-2026:74380 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:74383 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:74429 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:74434 access.redhat.com: https://access.redhat.com/errata/RHSA-2026:79039 access.redhat.com: https://access.redhat.com/security/cve/CVE-2026-49329 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2483248
Credits
Red Hat would like to thank tonghuaroot for reporting this issue.