CVE-2026-52103 in SimpleX Chat
Summary
by MITRE • 08/26/2026
A zero-click remote code execution (RCE) vulnerability in the /Terminal/Notification.hs component of SimpleX Chat before v6.5 allows attackers to execute arbitrary commands in the context of the application without user interaction via sending a crafted payload in a text message.
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Analysis
by VulDB Data Team • 08/26/2026
The identified vulnerability represents a critical security flaw within the notification handling subsystem of SimpleX Chat, specifically located in the Terminal/Notification.hs component prior to version 6.5. This defect is classified as a zero-click remote code execution (RCE) vulnerability, which signifies that an attacker can achieve complete control over the target application and potentially the underlying operating system without any action required from the victim user. Unlike vulnerabilities requiring social engineering or physical access, this flaw allows for fully automated exploitation through network-based vectors, specifically by injecting malicious payloads into text messages received by the application. The absence of user interaction significantly lowers the barrier to entry for attackers and increases the likelihood of successful compromise in targeted campaigns where victims may be cautious about clicking links or opening attachments but cannot easily avoid receiving incoming communications.
From a technical perspective, the root cause lies in improper validation or sanitization of input data processed by the notification module when rendering or handling message content. The application likely fails to properly escape special characters or restricts execution contexts within the terminal emulation layer used for displaying notifications. When a crafted payload is embedded in an incoming text message, the parser interprets specific sequences as executable commands rather than literal string data. This misinterpretation allows arbitrary code injection into the process context of SimpleX Chat. The severity of this issue is compounded by its location; notification systems often run with elevated privileges or have broad access to system resources to provide timely alerts, making successful exploitation particularly dangerous for overall device security.
The operational impact of this vulnerability extends beyond simple application compromise. Successful exploitation grants an attacker the ability to execute arbitrary commands on the victim's device within the context of the SimpleX Chat process. This can lead to data exfiltration, where sensitive chat history, cryptographic keys, or personal identifiable information is stolen. Furthermore, it enables persistent backdoor installation, allowing attackers to maintain long-term access even if the application is restarted. In mobile environments, this could potentially facilitate further lateral movement or privilege escalation depending on the sandboxing mechanisms in place for the operating system. The zero-click nature means that victims are vulnerable simply by having their device connected to a network and receiving messages from malicious actors, making it suitable for high-value targeting operations such as espionage or surveillance campaigns.
This vulnerability aligns with Common Weakness Enumeration (CWE) categories including CWE-94 Improper Control of Generation of Code ('Code Injection') and CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'). In the context of the MITRE ATT&CK framework, this exploit technique corresponds to T1059 Command and Scripting Interpreter, specifically leveraging native command shells or scripting engines available on the target platform. The attack vector is classified as Network-based with a complexity rating that reflects its zero-click nature, making it highly effective for automated exploitation tools designed to scan large populations of vulnerable devices.
Mitigation strategies must prioritize immediate software updates. Users and administrators should upgrade SimpleX Chat to version 6.5 or later, where the input validation logic in the Terminal/Notification.hs component has been corrected to properly sanitize incoming message data before processing it through the notification renderer. For organizations deploying this application on managed devices, enforcing update policies via mobile device management (MDM) solutions is critical to ensure all endpoints are patched against this specific threat vector. Additionally, network-level monitoring can be employed to detect anomalous traffic patterns associated with exploitation attempts, although given the zero-click nature, endpoint detection and response (EDR) tools that monitor for unusual process creation or command execution within chat applications will provide a necessary layer of defense in depth until patches are applied.