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🛡️ CVE-2026-9798 — build-of-keycloak

🟡 CVSS 4.3 — Medium ✅ No Known Exploit CWE-305 NVD
4.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Keycloak has an Authentication Bypass by Primary Weakness

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: Required — someone has to click, open or visit something.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
  • Integrity impact: None.
  • Availability impact: None.

Weakness class

CVE-2026-9798 is classified as CWE-305: Authentication Bypass by Primary Weakness. The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.

Affected software

CVE-2026-9798 is recorded against 2 packages.

  • build-of-keycloak
  • org.keycloak:keycloak-services (from 26.5.0)

Timeline and source

Published on 28 May 2026 and last revised on 5 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
access.redhat.com
bugzilla.redhat.com

Other advisories for this package

build-of-keycloak has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-305: Authentication Bypass by Primary Weakness) in other software:

Details

Severity MEDIUM
CVSS Score 4.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
CWE CWE-305
Public Exploit ✅ No
Source NVD
Published 2026-05-28
Updated 2026-08-20
Modified 2026-08-05
Fix URL N/A

Affected Packages

Software From version Fixed in
build-of-keycloak — —
org.keycloak:keycloak-services 26.5.0 —

Similar Threats

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