What is CVE-2026-16103?
A flaw was found in the keycloak-services component of Keycloak. This issue is an incomplete fix for CVE-2026-9798, where brute-force protection checks were added to the Client-Initiated Backchannel Authentication (CIBA) initiation handler but were omitted from the token redemption handler. This allows an attacker with valid client credentials to obtain access and refresh tokens for a user account that has been locked due to brute-force protection, provided the authentication request was started before the lockout occurred and was approved by the user.
The record classifies CVE-2026-16103 under weakness classes CWE-305, CWE-841. 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 103 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)
- 0.3% probability of exploitation in the next 30 days, higher than 25.9% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 3.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-07-17, last modified 2026-08-31
Is CVE-2026-16103 being exploited?
It currently carries a trending score of 20 in the Threadlinqs vulnerability feed.
Affected products and versions
- Red Hat: Build of Keycloak, Data Grid 8, JBoss Enterprise Application Platform Expansion Pack, Single Sign-On 7
How to fix CVE-2026-16103
No vendor patch reference has been recorded for CVE-2026-16103 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-2026-16103
1 tracked threat in the Threadlinqs corpus references CVE-2026-16103, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on .