CVE-2026-9798
Keycloak: keycloak: brute-force protection bypass in ciba flow
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
4.3
Keycloak: keycloak: brute-force protection bypass in ciba flow
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.
- Record
CVE-2026-9798- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N - Weakness
- CWE-305
- Updated
- 2026-11-02
EUVDEUVD-2026-32717
4.3
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.
- Record
EUVD-2026-32717- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-q6h7-xxp7-7429
4.3
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.
- Record
GHSA-q6h7-xxp7-7429- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N - Weakness
- CWE-305
- Updated
- 2026-11-02
NVD
4.3
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.
- Record
CVE-2026-9798- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N - Weakness
- CWE-305
- Updated
- 2026-11-02
OSVGHSA-q6h7-xxp7-7429
4.3
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.
- Record
GHSA-q6h7-xxp7-7429- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N - Weakness
- CWE-305
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.keycloak:keycloak-servicesMaven |
through 26.4.7 | None known |
org.keycloak:keycloak-servicesMaven |
26.5.0 to 26.6.4 | None known |
org.keycloak:keycloak-servicesMaven |
through 26.4.7, plus listed versions 1.0-alpha-11.0-alpha-1-120620131.0-alpha-21.0-alpha-31.0-alpha-4 Show 45 moreShow less1.0-beta-11.0-beta-1-201505211.0-beta-1-201505231.0-beta-21.0-beta-31.0-beta-41.0-final1.0-rc-11.0-rc-21.0.1.Final1.0.2.Final1.0.3.Final1.0.4.Final1.0.5.Final1.1.0.Beta11.1.0.Beta21.1.0.Final1.1.1.Final1.2.0.Beta11.2.0.CR11.2.0.Final1.3.0.Final1.3.1.Final1.4.0.Final1.5.0-Final1.5.0.Final1.5.1.Final1.6.0.Final1.6.1.Final1.7.0.CR11.7.0.Final1.8.0.Alpha11.8.0.CR11.8.0.CR21.8.0.CR31.8.0.Final1.8.1.Final1.9.0.CR11.9.0.Final1.9.1.Final1.9.2.Final1.9.3.Final1.9.4.Final1.9.5.Final1.9.7.Final |
None known |
org.keycloak:keycloak-servicesMaven |
26.5.0 to 26.6.4, plus listed versions 26.5.126.5.226.5.326.5.426.5.5 Show 6 moreShow less26.5.626.5.726.6.026.6.126.6.226.6.3 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-9798 is a medium vulnerability (CVSS 4.3) in Red Hat Build Of Keycloak 26.4, published May 28, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.38%, the 31st percentile. No source names a fixed version.
References
access.redhat.com/errata/RHSA-2026:50846
access.redhat.com/errata/RHSA-2026:50847
access.redhat.com/errata/RHSA-2026:50848
access.redhat.com/errata/RHSA-2026:50849
access.redhat.com/security/cve/CVE-2026-9798
bugzilla.redhat.com/show_bug.cgi?id=2482470
Show 10 moreShow less
nvd.nist.gov/vuln/detail/CVE-2026-9798
github.com/keycloak/keycloak/issues/49432
github.com/keycloak/keycloak/pull/49791
github.com/keycloak/keycloak/pull/49903
github.com/keycloak/keycloak/pull/49905
github.com/keycloak/keycloak/commit/11c2695064cd93da1d333df3f69d4a4141e86c29
github.com/keycloak/keycloak/commit/2edc6b112e2dedce63062b89ab3c7ae542e0d9ac
github.com/keycloak/keycloak/commit/a11e3254efc16ae72ce5092b93b9f557a4ba43ae
github.com/advisories/GHSA-q6h7-xxp7-7429
github.com/keycloak/keycloak
Left out here: 165 versions. The JSON record has them.