CVE detail
CVE-2026-37977
A flaw was found in Keycloak. A remote attacker can exploit a Cross-Origin Resource Sharing (CORS) header injection vulnerability in Keycloak's User-Managed Access (UMA) token endpoint. This flaw occurs because the `azp` claim from a client-supplied JSON Web Token (JWT) is used to set the `Access-Control-Allow-Origin` header before the JWT signature is validated. When a specially crafted JWT with an attacker-controlled `azp` value is processed, this value is reflected as the CORS origin, even if the grant is later rejected. This can lead to the exposure of low-sensitivity information from authorization server error responses, weakening origin isolation, but only when a target client is misconfigured with `webOrigins: ["*"]`.
Buzz score
Why this CVE is surfacing
This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.
Buzz score components · mention 19.5 · diversity 10.0 · KEV 0.0 · OTX 0.0 · PoC 0.0
Why it matters now
Mention timeline
- Total mentions
- 0
- within the 30d window
- Peak daily
- 0
- highest bucket
Evidence
Source links by recency
6 source links · newest first
- https://bugzilla.redhat.com/show_bug.cgi?id=2455324bugzilla.redhat.com
No excerpt available.
Exploitbugzilla.redhat.comApr 6, 2026, 9:16 AM - https://access.redhat.com/security/cve/CVE-2026-37977access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comApr 6, 2026, 9:16 AM - https://access.redhat.com/errata/RHSA-2026:30050access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comApr 6, 2026, 9:16 AM - https://access.redhat.com/errata/RHSA-2026:30049access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comApr 6, 2026, 9:16 AM - https://access.redhat.com/errata/RHSA-2026:25098access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comApr 6, 2026, 9:16 AM - https://access.redhat.com/errata/RHSA-2026:25097access.redhat.com
No excerpt available.
Vendor Advisoryaccess.redhat.comApr 6, 2026, 9:16 AM
Exploit code
Public exploit repository references
Public PoC repositories are third-party, potentially unsafe artifacts. Treat their code as untrusted and use it only on authorized systems in an isolated, least-privilege environment. cvebuzz does not execute the code or verify that an exploit works.
0 repository references · best confidence N/A · max 0 stars
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