External risk intelligence

Tarnhelm Insecure Permissions Allow Data Access and Overwriting

CVE advisorySeverity: CRITICAL (CVSS 9.1)

CVE-2026-107027

The vulnerability involves insecure permissions and an exported component in an Android application (Tarnhelm). Android exported components are typically accessible only by other applications installed on the same local device, not by remote internet-facing services or public network entities. Therefore, it lacks the characteristics of an internet-facing attack surface.

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This advisory concerns a critical security vulnerability discovered in the Tarnhelm application. The issue stems from insecure permissions that could allow unauthorized access, leading to the potential for arbitrary data exposure and modification. While the technical details involve specific application components, the high-level risk is that sensitive information could be compromised or altered without proper authorization.

Insecure app permissions allow unauthorized access.
Potentially exposes and modifies sensitive data.
Confirm relevance to understand actual exposure.

Attack Path

How an attacker could exploit the issue

An attacker could gain unauthorized access to an Android application by exploiting insecure permissions. This allows them to trigger an exported component within the app, potentially leading to the exposure and modification of sensitive data.

No authentication or privileges required.
Trigger exported component via insecure permissions.
Arbitrary data access and overwriting risk.

Live Threat

Current exploitation, exposure, and threat context

Insecure permissions in lz233 Tarnhelm could allow unauthorized parties to access and modify application data. This occurs when an exported component within the application is invoked without proper safeguards.

Application data at risk.
Unauthorized component invocation.
Data access and modification.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Tarnhelm application's exported component, vulnerable to unauthorized data access and overwriting due to insecure permissions, likely falls under the responsibility of the application owner or the team managing Android devices. The first practical step is to identify all instances of Tarnhelm, assess their business criticality and network reachability, and then assign ownership for remediation planning.

App owners should confirm Tarnhelm deployment.
Verify app reachability and business criticality.
Plan remediation based on identified risk.

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 the Tarnhelm app?

Tarnhelm is an Android application, identified as lz233 Tarnhelm v1.8.2, designed to manage specific data tasks on mobile devices. Like many Android tools, it uses internal components to perform functions; in this version, one of those components was configured with overly broad permissions, making it accessible to other local apps.

What does CWE-926 mean for CVE-2026-107027?

CWE-926 refers to improper export of Android application components. In the context of CVE-2026-107027, this means the app exposed a internal feature to other applications on the same device without checking their identity. Because this "door" was left unlocked, any malicious app on the same phone could potentially walk through it to read or overwrite the data Tarnhelm manages.

How can an attacker trigger this vulnerability?

An attacker needs to run a malicious application on the same Android device where Tarnhelm is installed. They cannot trigger this bug remotely from the internet. The vulnerability does not activate if the attacker does not have the ability to execute code locally on the device or if the device lacks a secondary app capable of communicating with Tarnhelm's exported component.

Is this CVE an internet-facing threat?

No. According to Halo Surface Signal, this vulnerability is not considered internet-facing. Because it relies on Android's local inter-app communication, it is limited to the physical or virtual device. It is generally not reachable by remote network entities or public servers, which significantly narrows the scope of concern for most organizations.

How should I respond if I use Tarnhelm?

Begin by auditing your mobile environment to locate where Tarnhelm is currently installed. Once identified, evaluate whether the application is still required for your business operations. If it remains necessary, consult your device management team to monitor for updates or official guidance on restricting access to the application's components.

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.