External risk intelligence

Apache Answer Reaction API Missing Authentication

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-90910

Apache Answer is a Q&A platform typically deployed as a public-facing web application. Since the vulnerability exists within the application's API, which is designed to be accessible to users interacting with the web interface or programmatic clients, it is commonly exposed to the internet in standard deployment configurations.

Missing Authentication

Halo Surface Signal: 4 out of 5 — likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability has been identified in Apache Answer, a Q&A platform, which could allow unauthorized users to access or manipulate reaction data on restricted content. This issue stems from the reaction API not properly enforcing content visibility controls, potentially impacting user privacy and data integrity. The main concern is to confirm if this specific technology is in use and assess any exposure.

Unrestricted reactions on private content.
Could expose sensitive user interactions.
Confirm relevance and scope.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by accessing the reaction API without proper authentication, allowing them to view or manipulate reactions on any content. This could lead to unauthorized access to sensitive information or disruption of user interactions.

No authentication needed for API.
Call the reaction API.
Unauthorized data access or modification.

Live Threat

Current exploitation, exposure, and threat context

Missing authentication in the reaction API could allow unauthorized users to view reaction metadata from restricted content or manipulate reactions. This behavior is supported when the reaction API is accessed without proper authentication.

Restricted content's reaction metadata.
Unauthorized API access.
Data exposure and manipulation.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Apache Answer application, particularly its reaction API, presents a critical vulnerability due to missing authentication. Teams responsible for this application, likely including platform or application owners and potentially the vendor-management team if it's a third-party solution, should first identify all instances of Apache Answer within their environment and assess their exposure. Confirming reachability and business criticality will guide prioritization for remediation, which involves coordinating with the appropriate teams to plan for an upgrade to a fixed version.

Identify accountable application/platform owners.
Verify public internet exposure and criticality.
Plan upgrade for affected instances.

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 Answer?

Apache Answer is an open-source Q&A platform designed to help teams build knowledge-sharing communities. It functions similarly to other forum-based applications where users post questions and interact with content through reactions, such as upvotes or emojis.

What does CWE-306 mean for CVE-2026-90910?

CWE-306 refers to a Missing Authentication for Critical Function vulnerability. In this case, the software fails to verify the identity of a user before allowing them to access the reaction API, which should be protected. Because of this weakness, the system treats unauthenticated requests as legitimate, allowing them to bypass visibility restrictions.

How can an attacker trigger this vulnerability?

An attacker can trigger this by sending direct, unauthenticated requests to the application's reaction API. The flaw does not require the user to have an account or be logged in to function. Simply interacting with the API endpoints allows them to read restricted metadata or change reactions, even on content they are not authorized to see.

Is my instance of Apache Answer at risk?

According to Halo Surface Signal, this software is typically deployed as a public-facing web application, making it highly likely to be exposed to the internet. If your instance is reachable from the public web, it is accessible to unauthorized users who can exploit the API, regardless of whether the content is intended to be private or restricted.

How do I secure my environment against this?

The primary response is to update your software. The maintainers have released version 2.0.3, which specifically addresses the authentication oversight in the reaction API. You should inventory all deployed instances of Apache Answer in your environment and prioritize upgrading them to this version to restore proper access controls.

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.