External risk intelligence

DIA eObčanka-Identifikace MacOS Command Injection via Custom URL Scheme

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2026-59111

The vulnerability resides in a desktop client application (eObčanka-Identifikace on MacOS) that requires the user to interact with a custom URL scheme. While reachable via network-delivered links, it is a client-side end-user application rather than a public-facing server, gateway, or edge service.

OS Command Injection

Halo Surface Signal: 2 out of 5 — less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in the eObčanka-Identifikace application on macOS could allow an attacker to execute arbitrary commands by tricking a user into opening a specially crafted URL. This issue stems from how the application handles parameters passed through its custom URL scheme, potentially leading to unauthorized actions on a user's system.

Custom URLs could run unwanted commands.
Remember this impacts macOS eObčanka users.
Confirm if your macOS systems are exposed.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by tricking a user into clicking a specially crafted link that registers a custom URL scheme. This link would pass unsanitized parameters to an AppleScript wrapper, which could then execute arbitrary operating system commands. This could occur if the application is installed and the user interacts with a malicious link, potentially leading to significant system compromise.

User interaction with a malicious link is required.
Crafted URL parameters trigger command execution.
Risk of unauthorized OS command execution.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow an attacker to execute arbitrary commands on a macOS system when a user interacts with a specially crafted URL. This occurs because the application improperly handles parameters passed through a custom URL scheme, potentially leading to unintended command execution.

System commands on macOS.
User clicks a malicious URL.
Arbitrary command execution.

Operational Fix

Recommended remediation, mitigation, and detection steps

The Digitální a informační agentura (DIA) eObčanka-Identifikace application on macOS is affected by this vulnerability. Application owners and infrastructure teams should prioritize identifying instances of this software, confirming its reachability and criticality, and then coordinating remediation efforts.

Application owners should own the issue.
Verify user interaction and network reachability.
Plan remediation based on risk assessment.

Supplementary metadata

CVSS vector

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Frequently asked questions

What is the eObčanka-Identifikace application used for?

The eObčanka-Identifikace application, developed by the Digitální a informační agentura (DIA), is a desktop software used on macOS for identity verification and authentication processes. It helps users manage digital identification tasks securely by interacting with government systems through specific protocols, such as the czeeopauth:// custom URL scheme used for application integration.

How does CVE-2026-59111 cause an OS command injection?

This vulnerability is classified as CWE-78, or OS Command Injection. It occurs because the application improperly sanitizes parameters passed through its custom URL scheme. When a user clicks a malicious link, these unsanitized parameters are concatenated directly into an internal AppleScript wrapper, allowing an attacker to insert and execute unintended commands on the underlying operating system.

When does this vulnerability trigger?

The vulnerability triggers when a user interacts with a specially crafted URL that invokes the czeeopauth:// scheme. Importantly, simply having the application installed does not trigger the bug. It requires an active, malicious link that forces the application to process dangerous input; standard use of the application with legitimate identification services does not trigger this execution path.

Is my system at risk if I use eObčanka-Identifikace?

According to Halo Surface Signal, this is an end-user client application rather than a public-facing server or gateway. Because the attack relies on the user clicking a link, the risk depends on user activity. While the vulnerability is classified as external, it is not automatically reachable from the internet like a network service; it requires someone to follow a link that interacts with the desktop software.

How should I respond to this vulnerability?

You should verify if you have the affected macOS version of eObčanka-Identifikace installed. Since the issue was addressed in version 3.6.0, your primary step is to check for and apply all available software updates from the official provider. In the meantime, exercise caution when clicking suspicious links, especially those formatted as czeeopauth://, which may attempt to interact with the application.

References

info.identita.gov.cz/eop/BezpecnostniOznameni/CVE-2026-59111.aspx

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.