CVE-2025-9800 is a medium-severity vulnerability affecting the SimStudioAI sim product, specifically in the HTML File Parser component's Import function located in apps/sim/app/api/files/upload/route.ts. The vulnerability arises from improper validation or restriction of the File argument during the upload process, allowing an attacker to perform an unrestricted file upload. This flaw can be exploited remotely without requiring user interaction or elevated privileges, as indicated by the CVSS vector (AV:N/AC:L/PR:L/UI:N). The vulnerability impacts confidentiality, integrity, and availability to a limited extent (VC:L/VI:L/VA:L), suggesting that uploaded files could potentially be malicious or unauthorized, leading to code execution, data manipulation, or service disruption. The product uses a rolling release model, so affected versions are identified by commit hashes rather than traditional version numbers, with the vulnerable commit being ed9b9ad83f1a7c61f4392787fb51837d34eeb0af. A patch identified by commit 45372aece5e05e04b417442417416a52e90ba174 addresses this issue. Although no known exploits are currently in the wild, the exploit code has been publicly disclosed, increasing the risk of exploitation. The vulnerability's ease of exploitation combined with remote attack vector makes it a significant concern for organizations using SimStudioAI sim, especially those exposing the upload functionality to external networks.

For European organizations, this vulnerability poses a risk of unauthorized file uploads that could lead to remote code execution, data breaches, or denial of service conditions. Organizations in sectors such as software development, AI research, and digital content creation that rely on SimStudioAI sim may face operational disruptions or compromise of sensitive data. The medium severity rating reflects a moderate risk, but the public availability of exploit code increases the urgency for remediation. Exploitation could lead to lateral movement within networks or serve as a foothold for further attacks. Given the remote attack vector and lack of required user interaction, attackers can automate exploitation attempts, potentially targeting multiple organizations simultaneously. This could impact compliance with European data protection regulations such as GDPR if personal data is exposed or manipulated. Additionally, disruption of AI simulation workflows could affect innovation and productivity in technology-driven sectors.

European organizations should immediately identify instances of SimStudioAI sim in their environments and verify if they are running vulnerable commits. Applying the patch corresponding to commit 45372aece5e05e04b417442417416a52e90ba174 is critical. If patching is not immediately feasible, organizations should implement strict network segmentation to isolate systems running the vulnerable software, limiting exposure to untrusted networks. Deploy web application firewalls (WAFs) with rules to detect and block suspicious file upload patterns targeting the affected endpoint. Enforce strict file type validation and scanning on upload endpoints to prevent malicious payloads. Monitor logs for unusual upload activity or failed attempts. Employ intrusion detection systems (IDS) tuned to detect exploitation attempts of this vulnerability. Additionally, review and tighten permissions for the upload functionality to ensure only authenticated and authorized users can upload files, even though the vulnerability does not require user interaction, reducing attack surface. Conduct regular security assessments and penetration tests focusing on file upload mechanisms. Finally, maintain awareness of vendor updates and threat intelligence feeds for any emerging exploit campaigns.