CVE-2026-53561 in Hive
Summary
by MITRE • 08/25/2026
An improper authentication vulnerability in HiveServer2 SAML bearer-token validation in Apache Hive 4.0.0 through 4.2.0 (and later unreleased branches) on deployments using HTTP transport with hive.server2.authentication=SAML allows an unauthenticated network attacker to authenticate as an arbitrary Hive user and obtain an authenticated HiveServer2 session via a forged Authorization: Bearer token sent to the /cliservice HTTP endpoint. Users are recommended to upgrade to 4.2.1 version that includes the fix for this issue.
Access / authorization required: No Hive credentials, SAML IdP login, or knowledge of the server signing secret is required. The attacker only needs network reachability to the HiveServer2 HTTP port (typically /cliservice), directly or through a reverse proxy such as Apache Knox that forwards unauthenticated requests to HS2. The instance must have SAML authentication enabled in HTTP mode. Deployments where Knox handles SSO and HiveServer2 uses LDAP/Kerberos (not native SAML mode) are not affected by this specific issue.
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability identified as an improper authentication flaw within Apache Hive 4.0.0 through 4.2.0 represents a critical security failure in the handling of Security Assertion Markup Language bearer tokens during HTTP transport operations. This defect specifically impacts deployments where the hive.server2.authentication configuration is explicitly set to SAML, allowing unauthenticated network attackers to bypass access controls entirely. The core technical flaw lies in the validation logic for incoming Authorization headers containing Bearer tokens at the /cliservice HTTP endpoint. Instead of rigorously verifying the cryptographic signature and integrity of the token against a trusted identity provider or server signing secret, the system accepts forged tokens that claim arbitrary user identities. This allows an attacker to impersonate any valid Hive user without possessing legitimate credentials, SAML Identity Provider login sessions, or knowledge of the private keys used for token signing. The absence of proper validation means that the authentication mechanism is effectively nullified, reducing it to a mere identity assertion rather than a verified proof of authority.
From an operational perspective, this vulnerability enables complete unauthorized access to the HiveServer2 instance and its underlying data warehouse resources. An attacker with network reachability to the HiveServer2 HTTP port can directly inject malicious SQL queries or extract sensitive data by authenticating as high-privilege users such as administrators or service accounts. The attack vector is particularly dangerous because it does not require any prior compromise of user credentials or identity provider systems. Furthermore, the risk is amplified in environments utilizing reverse proxies like Apache Knox for single sign-on management. If these proxies forward unauthenticated requests to HiveServer2 without stripping or validating the Authorization header appropriately, they inadvertently facilitate this bypass. Deployments where Knox handles SSO and HiveServer2 relies on LDAP or Kerberos authentication are not susceptible to this specific flaw, highlighting that the issue is strictly tied to native SAML mode over HTTP transport rather than other authentication mechanisms or secure transports like HTTPS with mutual TLS.
This vulnerability aligns closely with CWE-287 Improper Authentication, as it involves a failure in verifying user identity before granting access. Additionally, it maps to MITRE ATT&CK technique T1078 Valid Accounts, where an attacker uses legitimate credentials or forged identities to maintain persistence and move laterally within the environment. The ability to authenticate as arbitrary users allows for data exfiltration, privilege escalation if the impersonated user has elevated permissions, and potential denial of service through resource exhaustion via malicious queries. To mitigate this risk, organizations must immediately upgrade Apache Hive to version 4.2.1 or any subsequent release that includes the corrected validation logic for SAML bearer tokens. For deployments unable to upgrade instantly, applying network-level access controls such as firewall rules to restrict HTTP port access only to trusted IP ranges can provide temporary relief. Additionally, ensuring that reverse proxies like Knox enforce strict authentication checks before forwarding requests to HiveServer2 is crucial in mixed-environment setups where the specific SAML vulnerability might be bypassed through proxy misconfiguration.