CVE-2026-9798 — Red Hat build of Keycloak 26.4

What is CVE-2026-9798?

A flaw was found in Keycloak, an open-source identity and access management solution. When a user account is temporarily locked due to repeated failed login attempts, an attacker with valid client credentials can exploit the Client-Initiated Backchannel Authentication (CIBA) flow to bypass this brute-force protection. This allows continued authentication attempts and token issuance even when the account should be locked, potentially enabling further unauthorized access attempts.

The record classifies CVE-2026-9798 under weakness class CWE-305. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first. 4 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 153 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 4.3 — MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
EPSS (FIRST): 0.4% probability of exploitation in the next 30 days, higher than 40.2% of all scored CVEs
CISA KEV: Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority: 3.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published: 2026-05-28, last modified 2026-08-20

Is CVE-2026-9798 being exploited?

It currently carries a trending score of 15 in the Threadlinqs vulnerability feed.

Affected products and versions

Red Hat: build of Keycloak 26.4, build of Keycloak 26.4.14, build of Keycloak 26.6, build of Keycloak 26.6.5

Affected software packages:

maven:org.keycloak:keycloak-services
maven:org.keycloak:keycloak-services

How to fix CVE-2026-9798

No vendor patch reference has been recorded for CVE-2026-9798 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-9798

1 tracked threat in the Threadlinqs corpus references CVE-2026-9798, either in the campaign’s CVE list or as an indicator on the campaign record.

CVE-2026-17059: Keycloak Admin REST API Broken Object-Level Authorization Exposes User PII — MEDIUM · 2026-07-31

Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-10-10.