CVE-2026-84887 in Agent-S
Summary
by MITRE • 09/03/2026
A vulnerability was identified in simular-ai Agent-S up to 0.3.2. Affected by this issue is some unknown functionality of the file grounding.py of the component Model-generated GUI Action Execution Workflow. The manipulation leads to denial of service. Remote exploitation of the attack is possible. The exploit is publicly available and might be used. The vendor was contacted early about this disclosure but did not respond in any way.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 09/03/2026
The vulnerability identified within simular-ai Agent-S versions up to 0.3.2 represents a significant security risk due to its potential for remote exploitation and the resulting denial of service impact. This flaw resides specifically within the file grounding.py, which is an integral component of the Model-generated GUI Action Execution Workflow subsystem. The nature of this vulnerability suggests that the application fails to properly validate or handle specific inputs during the execution of model-driven actions against graphical user interfaces. When manipulated, these improper input handling mechanisms trigger a state in the software where it becomes unable to continue normal operations, effectively causing a crash or hang condition. This aligns with common patterns found in CWE-20 Improper Input Validation and CWE-400 Uncontrolled Resource Consumption, as the system likely enters an infinite loop, exhausts memory resources, or encounters an unhandled exception that terminates the process without graceful recovery mechanisms.
The operational impact of this vulnerability is severe for any organization relying on simular-ai Agent-S for automated GUI testing or interaction workflows. Since the exploit allows for remote exploitation, an attacker does not need physical access to the system and can trigger the denial of service condition over a network connection. This capability transforms what might otherwise be a local stability issue into a critical availability threat. The public availability of the exploit code further exacerbates this risk by lowering the barrier to entry for malicious actors who may lack sophisticated technical skills but possess automated scanning tools or scripts that leverage known vulnerabilities. Such attacks can lead to significant downtime, disruption of continuous integration and deployment pipelines, and potential data loss if stateful operations are interrupted abruptly during critical processes.
The vendor's failure to respond to early disclosure attempts leaves the community without an official patch or mitigation guidance from the primary source. This lack of communication forces security professionals and users to rely on community-driven analysis and workarounds rather than verified fixes. In such scenarios, it is crucial for administrators to implement network-level controls as a defensive measure. These may include restricting access to the affected service through firewall rules, implementing rate limiting to mitigate automated exploitation attempts, or deploying intrusion detection systems that can identify signatures associated with the known exploit code. Additionally, since this vulnerability affects the GUI action execution workflow, organizations should consider isolating these services in untrusted network segments and ensuring that any exposed endpoints are protected by web application firewalls capable of detecting anomalous input patterns typical of denial-of-service attacks against parsing engines.
From a threat intelligence perspective, this incident highlights the importance of maintaining visibility into open-source software dependencies used within automated testing frameworks. The ATT&CK framework categorizes such actions under T1499 Endpoint Denial of Service or potentially T1053 Scheduled Task/Job if the denial of service is part of a broader persistence strategy to disrupt security monitoring tools. Security teams should prioritize patching this vulnerability as soon as an official update becomes available, while simultaneously applying compensating controls in the interim period. Regular audits of third-party libraries and their associated vulnerabilities are essential to maintain the integrity and availability of automated systems that depend on model-generated actions for operational continuity.