CVE-2026-59111 Overview
CVE-2026-59111 is an OS command injection vulnerability in the Digitální a informační agentura (DIA) eObčanka-Identifikace application on macOS. The application registers the custom URL scheme czeeopauth:// and passes incoming URL parameters into a compiled AppleScript wrapper through string concatenation. Insufficient sanitization allows an attacker to inject arbitrary shell commands through crafted URLs. Exploitation requires user interaction, such as clicking a malicious link, but no authentication. The flaw is fixed in version 3.6.0.
Critical Impact
Attackers can execute arbitrary OS commands in the user context by luring victims to open a crafted czeeopauth:// URL, compromising confidentiality and integrity on affected macOS hosts.
Affected Products
- DIA eObčanka-Identifikace for macOS, versions prior to 3.6.0
- Systems that have registered the czeeopauth:// URL scheme handler
- macOS endpoints used for Czech eID authentication workflows
Discovery Timeline
- 2026-08-31 - CVE-2026-59111 published to NVD
- 2026-09-01 - Last updated in NVD database
Technical Details for CVE-2026-59111
Vulnerability Analysis
The eObčanka-Identifikace application registers czeeopauth:// as a custom URL scheme on macOS. When a browser or other application dispatches a URL using this scheme, macOS launches eObčanka-Identifikace and forwards the URL payload. The application then hands parameters to a compiled AppleScript wrapper that assembles a shell command using string concatenation. Because parameters are not sanitized, an attacker can inject shell metacharacters that break out of the intended argument and execute arbitrary commands. The vulnerability is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command).
Root Cause
The root cause is unsafe construction of an OS command from untrusted input. Parameters received via the czeeopauth:// URL scheme are concatenated directly into the AppleScript command string without escaping, quoting, or allow-listing. AppleScript's do shell script and similar constructs interpret shell metacharacters, letting attacker-controlled data change command semantics.
Attack Vector
Exploitation is remote and requires user interaction. An attacker hosts a page or sends a message containing a crafted czeeopauth:// URL. When the victim opens the link on a macOS host with a vulnerable eObčanka-Identifikace installed, macOS dispatches the URL to the application, which passes the malicious parameter into the AppleScript wrapper. The injected commands execute with the privileges of the current user. The scope change reflects that the injected commands leave the application boundary and act on the operating system shell.
No verified exploit code is published. See the Identita Security Advisory CVE-2026-59111 for vendor-authoritative technical details.
Detection Methods for CVE-2026-59111
Indicators of Compromise
- Invocation of eObčanka-Identifikace with czeeopauth:// URLs containing shell metacharacters such as ;, |, &, backticks, or $(...).
- Unexpected child processes such as /bin/sh, /bin/bash, osascript, curl, or nc spawned from the eObčanka-Identifikace process tree.
- Outbound network connections initiated by shells whose parent is the eID application.
Detection Strategies
- Monitor macOS process telemetry for eObčanka-Identifikace spawning shell interpreters or scripting hosts with suspicious arguments.
- Inspect LaunchServices handler registrations for the czeeopauth scheme and flag unexpected changes.
- Correlate browser URL launches of custom schemes with subsequent shell process creation events.
Monitoring Recommendations
- Alert on any osascript execution that includes shell metacharacters embedded in argument strings.
- Track installed versions of eObčanka-Identifikace across managed macOS fleets and flag versions earlier than 3.6.0.
- Log and review inbound URLs handled by custom schemes registered by identity or authentication applications.
How to Mitigate CVE-2026-59111
Immediate Actions Required
- Upgrade eObčanka-Identifikace on macOS to version 3.6.0 or later on all endpoints.
- Inventory macOS hosts with the czeeopauth:// handler registered and prioritize patching.
- Warn users against clicking czeeopauth:// links from untrusted sources until patching is complete.
Patch Information
The vendor addressed the flaw in eObčanka-Identifikace version 3.6.0 by removing unsafe concatenation of URL parameters into the AppleScript wrapper. Refer to the Identita Security Advisory CVE-2026-59111 for the official fix guidance and download location.
Workarounds
- Uninstall eObčanka-Identifikace on hosts that do not require Czech eID authentication until the update is deployed.
- Remove or disable the czeeopauth URL scheme handler in LaunchServices on vulnerable hosts.
- Restrict browsers from automatically dispatching custom URL schemes without user confirmation.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.