External risk intelligence

Apache Impala SAML2 Authentication Bypass Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-56207

Apache Impala is a distributed SQL query engine typically deployed within internal data centers or private networks for analytical processing. While the hs2-http interface handles authentication, it is not standard design to expose this service directly to the public internet, though it may be accessible in some environments or through misconfigured gateways.

Apache Impala

4.0.0 to before 4.5.2

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability in Apache Impala's authentication process could allow unauthorized users to impersonate others by altering their usernames. This occurs in the final step of SAML2 authentication for the hs2-http interface. While direct internet exposure of this interface is not standard, its potential accessibility warrants attention.

Impala authentication bypass allows user impersonation.
Confirms if this critical issue impacts your systems.
Understand potential access and data exposure risks.

Attack Path

How an attacker could exploit the issue

An attacker could reach the vulnerable component by interacting with Impala's hs2-http interface over the network. This interface is involved in SAML2 authentication. By manipulating this process, an attacker could alter the username during the final authentication step, effectively impersonating another user.

No specific access required.
Attackers can trigger via authentication.
Risk of unauthorized user access.

Live Threat

Current exploitation, exposure, and threat context

In Apache Impala, when the SAML2 authentication's bearer token signature isn't verified for the hs2-http interface, an attacker could impersonate other users. This could occur when the interface is accessible, potentially allowing unauthorized access to data processed by Impala.

User identity and access controls.
Unverified token allows impersonation.
Unauthorized access to data.

Operational Fix

Recommended remediation, mitigation, and detection steps

The signature verification flaw in Apache Impala's SAML2 authentication for the hs2-http interface requires attention from teams managing the Impala platform, likely data or analytics platform owners, and potentially the security team for broader SAML integration oversight. The immediate practical step is to identify all instances of affected Impala versions, determine their network exposure and criticality, and confirm the responsible ownership before planning remediation.

Data platform or application owners should lead.
Verify Impala instances and exposure.
Plan risk-based remediation with vendors.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is Apache Impala?

Apache Impala is a distributed SQL query engine designed for high-performance, low-latency analysis on large datasets. It is commonly used by data engineers and analysts to perform interactive queries directly on data stored in systems like Hadoop. The hs2-http interface allows clients to connect to this engine over the network to execute these queries.

What does CWE-347 mean for CVE-2026-56207?

CWE-347 refers to improper verification of cryptographic signatures. In this CVE, the vulnerability occurs because Impala fails to verify the signature of a SAML2 bearer token during the final authentication step. Because the system does not confirm that the token is genuine, an attacker can modify the username inside the token, tricking the system into accepting them as a different, potentially more privileged user.

How is this authentication bypass triggered?

An attacker triggers this by interacting with the hs2-http interface during the SAML2 authentication flow. By submitting a manipulated token that lacks a valid signature, the attacker bypasses the identity check. This issue specifically impacts the authentication handshake; it does not involve exploiting underlying database queries or system commands directly.

Is my Apache Impala deployment at risk?

Your risk depends on network access. According to Halo Surface Signal, Apache Impala is typically hosted in internal data centers or private networks. If your hs2-http interface is only reachable within these private segments, the risk is lower. However, if the interface is exposed to the internet or reachable through misconfigured gateways, the potential for unauthorized impersonation increases significantly.

Do I need to update my software to fix this?

Yes. To resolve this vulnerability, you should upgrade to Apache Impala version 4.5.2 or later. Before updating, identify all running instances of Impala in your environment to ensure comprehensive coverage. Coordinate with your data or platform engineering teams to schedule the upgrade, as this will involve restarting the affected service.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.