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Vulnerability record · CVE-2026-9793 · published 28 May 2026

CVE-2026-9793: Redhat build of keycloak improper verification of cryptographic signature vulnerability

Redhat · Build Of Keycloak

A flaw was found in Keycloak. When a JSON Web Encryption (JWE) encrypted request object is submitted, Keycloak may incorrectly process unsigned claims if the decrypted content is raw JSON, bypassing the configured signature policy. This allows a remote attacker to submit unauthorized claims, leading to a compromise of data integrity within the OpenID Connect (OIDC) authorization flow. While a redirect URI allowlist acts as a compensating control, this vulnerability violates OIDC Core and Financial-grade API (FAPI) signing requirements.

7.5 CVSS 3.1 High EPSS 0.26% · top 84.4% CWE-347 · Improper verification of cryptographic signature
7.5CVSS 3.1 base score
0.26%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References
20 Aug 2026Last modified by NVD

Description

A flaw was found in Keycloak. When a JSON Web Encryption (JWE) encrypted request object is submitted, Keycloak may incorrectly process unsigned claims if the decrypted content is raw JSON, bypassing the configured signature policy. This allows a remote attacker to submit unauthorized claims, leading to a compromise of data integrity within the OpenID Connect (OIDC) authorization flow. While a redirect URI allowlist acts as a compensating control, this vulnerability violates OIDC Core and Financial-grade API (FAPI) signing requirements.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://access.redhat.com/errata/RHSA-2026:50846
https://access.redhat.com/errata/RHSA-2026:50847
https://access.redhat.com/errata/RHSA-2026:50848
https://access.redhat.com/errata/RHSA-2026:50849
https://access.redhat.com/security/cve/CVE-2026-9793 Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2482460 Issue TrackingVendor Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-9793), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.