Keycloak, default Dynamic Client Registration policy mis-validates the claim path for User Property mappers, letting a standard account with a limited Initial Access Token forge administrative roles and reach full realm control; CVSS 8.1, fixed in 26.4.14 / 26.6.5 / 26.7.1

Valid accounts in cloud environments may allow adversaries to perform actions to achieve Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Cloud accounts are those created and configured by an organization for use by users, remote support, services, or for administration of resources within a cloud service provider or SaaS application. Cloud Accounts can exist solely in the cloud; alternatively, they may be hybrid-joined between on-premises systems and the cloud through syncing or federation with other identity sources such as Windows Active Directory.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network. The weakness in the system can be a software bug, a temporary glitch, or a misconfiguration.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗

Valid accounts in cloud environments may allow adversaries to perform actions to achieve Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Cloud accounts are those created and configured by an organization for use by users, remote support, services, or for administration of resources within a cloud service provider or SaaS application. Cloud Accounts can exist solely in the cloud; alternatively, they may be hybrid-joined between on-premises systems and the cloud through syncing or federation with other identity sources such as Windows Active Directory.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗

Adversaries may modify authentication mechanisms and processes to access user credentials or enable otherwise unwarranted access to accounts. The authentication process is handled by mechanisms, such as the Local Security Authentication Server (LSASS) process and the Security Accounts Manager (SAM) on Windows, pluggable authentication modules (PAM) on Unix-based systems, and authorization plugins on MacOS systems, responsible for gathering, storing, and validating credentials. By modifying an authentication process, an adversary may be able to authenticate to a service or system without using Valid Accounts.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges. Exploitation of a software vulnerability occurs when an adversary takes advantage of a programming error in a program, service, or within the operating system software or kernel itself to execute adversary-controlled code. Security constructs such as permission levels will often hinder access to information and use of certain techniques, so adversaries will likely need to perform privilege escalation to include use of software exploitation to circumvent those restrictions.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗

Valid accounts in cloud environments may allow adversaries to perform actions to achieve Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Cloud accounts are those created and configured by an organization for use by users, remote support, services, or for administration of resources within a cloud service provider or SaaS application. Cloud Accounts can exist solely in the cloud; alternatively, they may be hybrid-joined between on-premises systems and the cloud through syncing or federation with other identity sources such as Windows Active Directory.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗

Valid accounts in cloud environments may allow adversaries to perform actions to achieve Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Cloud accounts are those created and configured by an organization for use by users, remote support, services, or for administration of resources within a cloud service provider or SaaS application. Cloud Accounts can exist solely in the cloud; alternatively, they may be hybrid-joined between on-premises systems and the cloud through syncing or federation with other identity sources such as Windows Active Directory.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗

Adversaries may modify authentication mechanisms and processes to access user credentials or enable otherwise unwarranted access to accounts. The authentication process is handled by mechanisms, such as the Local Security Authentication Server (LSASS) process and the Security Accounts Manager (SAM) on Windows, pluggable authentication modules (PAM) on Unix-based systems, and authorization plugins on MacOS systems, responsible for gathering, storing, and validating credentials. By modifying an authentication process, an adversary may be able to authenticate to a service or system without using Valid Accounts.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗

Adversaries may modify authentication mechanisms and processes to access user credentials or enable otherwise unwarranted access to accounts. The authentication process is handled by mechanisms, such as the Local Security Authentication Server (LSASS) process and the Security Accounts Manager (SAM) on Windows, pluggable authentication modules (PAM) on Unix-based systems, and authorization plugins on MacOS systems, responsible for gathering, storing, and validating credentials. By modifying an authentication process, an adversary may be able to authenticate to a service or system without using Valid Accounts.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗

An adversary may forge SAML tokens with any permissions claims and lifetimes if they possess a valid SAML token-signing certificate. The default lifetime of a SAML token is one hour, but the validity period can be specified in the <code>NotOnOrAfter</code> value of the <code>conditions ...</code> element in a token. This value can be changed using the <code>AccessTokenLifetime</code> in a <code>LifetimeTokenPolicy</code>. Forged SAML tokens enable adversaries to authenticate across services that use SAML 2.0 as an SSO (single sign-on) mechanism.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗

Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users. Some systems may automatically restart critical applications and services when crashes occur, but they can likely be re-exploited to cause a persistent denial of service (DoS) condition.

Evidence: 2026-08-07/keycloak-saml-broker-signature-bypass-cve-2026-16443 · ATT&CK page ↗