The Browser Security Report 2025 reveals that the enterprise browser has evolved into a parallel and largely unmanaged threat surface, where identity, SaaS, and AI-related risks converge. Traditional security controls such as Data Loss Prevention (DLP), Endpoint Detection and Response (EDR), and Secure Service Edge (SSE) operate below the browser layer and thus miss critical activities occurring within browser sessions. Key emerging threats include unmanaged browser extensions, which act like supply chain implants with high or critical permissions, many sideloaded or published by unverified Gmail accounts and often outdated. GenAI tools accessed through personal accounts create a significant governance gap; employees frequently paste sensitive data (PII, PCI) into AI prompts, with 32% of corporate-to-personal data movement attributed to GenAI usage. AI browsers like OpenAI’s Atlas and Perplexity Browser integrate large language models directly into browsing, enabling real-time reading and processing of web content but creating new risks such as session memory leakage, invisible auto-prompting to third-party AI models, and cookie sharing that can lead to session hijacking. Furthermore, over two-thirds of SaaS logins occur outside of Single Sign-On (SSO), with many using personal credentials and reused passwords, complicating identity governance. Messaging apps and SaaS workflows increasingly rely on browser-based pasting rather than file uploads, facilitating unmonitored data exfiltration. Legacy tools do not inspect session-level activities such as which SaaS tabs are open or what data is pasted, leaving security teams blind to shadow AI usage, extension code changes, and session hijacking. The report advocates for session-native browser security controls that monitor copy/paste actions, detect unmanaged GenAI tools and extensions, enforce session isolation and SSO, and apply DLP to non-file-based interactions, all without disrupting user experience. This new approach is critical to addressing the modern browser threat surface and preventing next-generation data leaks and identity compromises.

For European organizations, this threat presents significant risks to data confidentiality, integrity, and compliance. The widespread use of unmanaged browser extensions and personal GenAI accounts increases the likelihood of sensitive data exfiltration, including personal identifiable information (PII) and payment card information (PCI), potentially leading to GDPR violations and hefty fines. The bypassing of SSO and use of personal credentials heighten the risk of identity theft and unauthorized access to corporate SaaS resources, undermining trust and operational continuity. The invisible nature of AI browsers and session hijacking techniques complicates detection and response efforts, increasing exposure to advanced persistent threats and insider risks. European enterprises with high SaaS adoption and reliance on browser-based workflows are particularly vulnerable to these evolving attack vectors. Additionally, the integration of AI tools without governance may lead to inadvertent data leakage to third-party cloud services, further complicating compliance with data residency and privacy regulations. The threat also challenges existing security architectures, necessitating investment in new browser-native security technologies and updated policies. Failure to address these risks could result in operational disruptions, reputational damage, regulatory penalties, and financial losses.

European organizations should adopt a multi-layered, browser-native security strategy that includes: 1) Deploying session-level monitoring tools capable of inspecting copy/paste actions, uploads, and extension behaviors within browser sessions to detect and block unauthorized data exfiltration. 2) Enforcing strict browser extension governance by whitelisting approved extensions, regularly auditing installed extensions, and blocking sideloaded or unverified extensions, especially those with high or critical permissions. 3) Implementing session isolation and enforcing SSO for all SaaS logins to prevent identity crossover and unauthorized access via personal credentials. 4) Integrating GenAI governance policies that restrict the use of unmanaged AI tools and personal accounts for corporate data processing, coupled with user training on the risks of pasting sensitive data into AI prompts. 5) Utilizing advanced browser security platforms that provide visibility into AI browser activities, including detection of auto-prompting and session memory leakage. 6) Enhancing identity and access management (IAM) controls to detect and respond to session hijacking attempts, including monitoring cookie usage and session tokens. 7) Collaborating with legal and compliance teams to align security controls with GDPR and other regional data protection requirements. 8) Conducting regular security awareness training focused on emerging browser and AI-related risks. These measures should be integrated into existing security operations without disrupting user productivity.