How severe is CVE-2026-16103?

CVE-2026-16103 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-16103 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-16103?

CVE-2026-16103 affects Redhat Build Of Keycloak. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-16103?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-16103 published?

CVE-2026-16103 was published on 2026-07-17 and last updated on 2026-08-31.

CVE-2026-16103

CVE-2026-16103 is a medium-severity vulnerability in Redhat Build Of Keycloak with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-305.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-305
Affected product: Redhat Build Of Keycloak
Published: 2026-07-17
Last modified: 2026-08-31

Description

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.

Frequently asked questions

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.
How severe is CVE-2026-16103?: CVE-2026-16103 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-16103 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-16103?: CVE-2026-16103 affects Redhat Build Of Keycloak. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-16103?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-16103 published?: CVE-2026-16103 was published on 2026-07-17 and last updated on 2026-08-31.

References

Affected products (1)

cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:-:*:*:*

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