NewsPublished 20 Nov 2025

Comet Browser Flaw Lets Hidden API Run Commands on Users’ Devices

Source Reddit InfoSec News

Description

A security flaw in Comet Browser allows a hidden API to execute commands on users' devices without their knowledge. This vulnerability could enable attackers to run arbitrary commands remotely, potentially compromising device confidentiality, integrity, and availability. Although no known exploits are currently in the wild, the flaw poses a medium-level risk due to its ability to bypass user interaction and authentication. European organizations using Comet Browser or related software may be at risk, especially if the browser has significant market penetration in their sectors. Mitigation requires immediate vendor patching once available, disabling or restricting the hidden API, and monitoring for unusual command execution behavior. Countries with higher usage of Comet Browser and strategic digital infrastructure are more likely to be targeted. Given the medium severity, organizations should prioritize detection and containment measures while awaiting official fixes.

Impact

For European organizations, this vulnerability could lead to unauthorized remote command execution on devices running Comet Browser, potentially resulting in data breaches, system compromise, or disruption of services. Confidentiality could be breached through data exfiltration, integrity compromised by unauthorized changes, and availability affected if attackers disrupt system operations. Sectors with high reliance on browser-based applications, such as finance, government, and critical infrastructure, face increased risks. The stealthy nature of the hidden API could allow persistent access and lateral movement within networks. Additionally, the lack of user interaction requirement makes it easier for attackers to exploit the flaw at scale. This could undermine trust in affected organizations and lead to regulatory penalties under GDPR if personal data is compromised.

Defensive guidance

Organizations should immediately inventory their use of Comet Browser and related software to assess exposure. Until patches are released, disable or restrict access to the hidden API if possible through configuration or endpoint protection controls. Employ network monitoring to detect unusual command execution or outbound connections originating from browsers. Implement strict application whitelisting and endpoint detection and response (EDR) solutions to identify and block suspicious activities. Educate users about the risk and encourage vigilance for abnormal device behavior. Coordinate with vendors for timely updates and apply patches as soon as they become available. Consider isolating critical systems from internet-facing browsers or using alternative browsers with stronger security postures. Regularly review and update incident response plans to address potential exploitation scenarios.

Summary

The Comet Browser flaw involves a hidden API that can be exploited to run commands on users' devices without their consent or awareness. This vulnerability essentially provides attackers with a backdoor to execute arbitrary code remotely, which could lead to unauthorized access, data theft, or system manipulation. The flaw does not currently have a CVSS score, but its characteristics suggest a medium severity level. The lack of known exploits in the wild indicates it may be newly discovered or not yet weaponized. The vulnerability's exploitation does not require user interaction or authentication, increasing its risk profile. However, the minimal discussion and low Reddit score imply limited current awareness or impact. The absence of patch links suggests that a fix is not yet publicly available, emphasizing the need for vigilance. The flaw's technical details remain sparse, but the ability to run commands remotely is a critical concern for endpoint security. Organizations relying on Comet Browser should consider this a significant threat vector until mitigated.

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Description

AI analysisMachine-generated, updated 20 Nov 2025, 12:41 UTC

Technical details

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