Cybersecurity researchers at Cato Networks have uncovered a critical vulnerability in Streamlit, the popular open-source framework used for building data applications and financial dashboards, that could enable threat actors to manipulate stock market data and conduct cloud account takeover attacks.
The vulnerability, discovered in February 2025, affects the widely used st.file_uploader function and has already been patched in version 1.43.2.
Technical Exploitation Enables Backend Access
The vulnerability stems from improper file type enforcement in Streamlit’s file upload widget, where restrictions were only applied client-side through JavaScript without server-side validation.
Security researchers demonstrated how attackers could use proxy tools like Burp Suite to intercept upload requests and bypass frontend restrictions by modifying file extensions during transit.
The attack chain involves uploading malicious files disguised as legitimate ones, such as renaming malicious.exe to appear as a PDF file.
In their proof-of-concept demonstration, researchers showed how this could escalate to directory traversal attacks, where threat actors modify uploaded filenames to ../../.ssh/authorized_keys and overwrite critical system files with their SSH public keys.
This technique grants passwordless remote access to compromised cloud instances running Streamlit applications.
The technical exploitation follows a systematic approach: reconnaissance of publicly accessible
Streamlit instances, interception of requests to alter file extensions and paths, overwriting of the authorized_keys file, establishment of SSH access, enumeration of the cloud environment, and finally, manipulation of the data pipeline.
Financial Markets Face Unprecedented Cyber Risk
The implications for financial institutions are particularly alarming, as Streamlit has become a go-to framework for building stock market dashboards, machine learning prototypes, and real-time financial data visualizations.
Cato Networks’ researchers demonstrated how compromised instances could manipulate ingestion of pipeline scripts, database values, and dashboard code, potentially leading to undetected market manipulation.
Such attacks could trigger cascading effects where automated trading systems respond to false signals, media sentiment shifts based on manipulated data, and investors follow fraudulent trends.
The researchers noted that “stock market dashboards may drive automated alerts, risk models, and internal strategy decisions, meaning the manipulation could trigger a chain reaction of portfolio adjustments”.
Streamlit, acquired by Snowflake in March 2022, acknowledged the vulnerability and released a patch introducing backend validation to enforce file-type restrictions.
Cato Networks has updated its SASE Cloud Platform with enhanced threat prevention capabilities targeting unauthorized file upload bypass attempts and abnormal filename path detection.
Organizations are urged to ensure that cloud instances hosting web applications implement proper network restrictions and access controls.
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