External risk intelligence

VitaFit Cloud API Broken Access Control Allows Unauthorized Data Access

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2026-54378

The vulnerability exists in a cloud API endpoint (POST /front/user/s3/token/) used by the VitaFit application. Cloud APIs for mobile or web applications are commonly exposed as internet-facing services to facilitate communication between client applications and backend infrastructure, making this type of endpoint a standard part of an externally reachable service surface.

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 in the VitaFit cloud API allows any authenticated user to access temporary AWS credentials. This could enable unauthorized users to view or modify data stored by other users, leading to potential data breaches and integrity issues.

Unauthenticated access to user data.
Confirms the need to assess impact.
Verify if our systems are affected.

Attack Path

How an attacker could exploit the issue

An attacker could begin by exploiting a flawed access control mechanism within the VitaFit cloud API. By authenticating to the system and then calling a specific endpoint designed to provide temporary storage access, an attacker can obtain AWS credentials. These credentials, if improperly limited, could then be used to access a shared storage bucket, potentially allowing the attacker to view, modify, or overwrite files belonging to other users, leading to unauthorized data exposure and manipulation.

Authenticated user can access endpoint.
Unrestricted credentials allow storage access.
Unauthorized cross-user data access.

Live Threat

Current exploitation, exposure, and threat context

An authenticated user could exploit a broken access control vulnerability in the VitaFit cloud API to obtain temporary AWS credentials. These credentials, when improperly scoped, may allow an attacker to access, list, or overwrite files in a shared storage bucket, leading to unauthorized cross-user data access and manipulation.

Other users' files in shared storage.
By exploiting temporary AWS credentials.
Unauthorized cross-user data access.

Operational Fix

Recommended remediation, mitigation, and detection steps

The VitaFit cloud API's broken access control vulnerability requires immediate attention from teams managing the application's backend infrastructure and cloud environment. The first practical step is to identify all instances of the VitaFit cloud API, confirm their reachability and business criticality, and locate the accountable owner for remediation planning.

Cloud and application platform teams own this.
Verify API endpoints and user access controls.
Plan and coordinate vendor-assisted remediation.

Supplementary metadata

CVSS vector

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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 the VitaFit cloud API?

The VitaFit cloud API is the backend infrastructure that powers the VitaFit mobile application. It acts as a bridge, allowing the app to communicate with cloud-based services and manage user data storage, such as health or fitness records, in Amazon Web Services (AWS) buckets.

How does CVE-2026-54378 happen?

This vulnerability is a broken access control issue, classified under CWE-522. It occurs because the API does not properly restrict permissions when a user requests temporary AWS credentials. Instead of receiving limited access, an authenticated user gains credentials that are too broad, allowing them to interact with data outside their own account.

Does any authenticated action trigger this bug?

Not every action triggers the vulnerability. It specifically requires a user to call the POST /front/user/s3/token/ endpoint. Simply browsing the application or using other API functions does not exploit this flaw; the security failure is localized to the logic that generates these specific storage access tokens.

Who is at risk from this cloud API issue?

Users of the VitaFit ecosystem should be concerned. According to Halo Surface Signal, this API is an internet-facing service designed to communicate between mobile clients and the cloud. Because it is externally reachable by design, the API is inherently exposed to the network, making the access control flaw reachable by any authenticated user.

How should I respond to this threat?

If you manage the backend infrastructure for this software, start by confirming the reachability of the API within your cloud environment. Identify the team responsible for these cloud endpoints and review the current access control configurations. Coordinating with the vendor to ensure the API correctly scopes and restricts storage credentials is the primary path to remediation.

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.