Keycloak: keycloak authorization header parsing leading to potential security control bypass
Summary
| CVE | CVE-2026-0707 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-01-08 04:15:56 UTC |
| Updated | 2026-06-08 12:16:29 UTC |
| Description | A flaw was found in Keycloak. The Keycloak Authorization header parser is overly permissive regarding the formatting of the "Bearer" authentication scheme. It accepts non-standard characters (such as tabs) as separators and tolerates case variations that deviate from RFC 6750 specifications. |
Risk And Classification
Primary CVSS: v3.1 5.3 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS: 0.000230000 probability, percentile 0.066970000 (date 2026-06-14)
Problem Types: CWE-551 | CWE-551 Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| 3.1 | CNA | CVSS | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4 | unaffected 26.4.10-1 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4 | unaffected 26.4-12 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4 | unaffected 26.4-12 * rpm | Not specified |
| CNA | Red Hat | Red Hat Build Of Keycloak 26.4.10 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/errata/RHSA-2026:3947 | [email protected] | access.redhat.com | |
| github.com/keycloak/keycloak/issues/49433 | [email protected] | github.com | |
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/errata/RHSA-2026:3948 | [email protected] | access.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-0707 | [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: Red Hat would like to thank Guanping Zhang for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-01-08T02:51:20.440Z | Reported to Red Hat. |
| CNA | 2026-01-07T00:00:00.000Z | Made public. |
Workarounds
CNA: To mitigate this issue, configure any front-end security controls, such as Web Application Firewalls (WAFs) or reverse proxies, to strictly validate and normalize the `Authorization` header before forwarding requests to Keycloak. This ensures that only standard Bearer token formats are processed, preventing potential bypasses.
There are currently no legacy QID mappings associated with this CVE.