CVE-2025-53791 is a medium-severity vulnerability classified under CWE-284 (Improper Access Control) affecting Microsoft Edge (Chromium-based), specifically version 1.0.0.0. This vulnerability allows an unauthorized attacker to bypass a security feature remotely over a network. The flaw arises from insufficient enforcement of access control mechanisms within the browser, potentially allowing attackers to circumvent restrictions intended to protect sensitive browser functions or data. The CVSS 3.1 base score is 4.7, reflecting a network attack vector (AV:N) with high attack complexity (AC:H), no privileges required (PR:N), but requiring user interaction (UI:R). The scope is changed (S:C), indicating that the vulnerability affects resources beyond the initially vulnerable component. The impact on confidentiality and integrity is low (C:L, I:L), with no impact on availability (A:N). No known exploits are currently reported in the wild, and no patches or mitigations have been linked yet. The vulnerability was reserved in July 2025 and published in September 2025. The improper access control could allow attackers to bypass security features, potentially exposing user data or enabling further attacks, but exploitation requires user interaction and is complex, limiting immediate risk. However, given Microsoft Edge's widespread use, the vulnerability warrants attention and remediation once patches become available.

For European organizations, this vulnerability poses a moderate risk primarily to confidentiality and integrity of data accessed or processed through Microsoft Edge. Since the attack vector is network-based and requires user interaction, phishing or social engineering campaigns could be used to exploit this flaw. Organizations with employees using the affected Edge version could see unauthorized access to browser-protected resources or data leakage. This could impact sensitive corporate information, session tokens, or internal web applications accessed via the browser. The medium severity and complexity reduce the likelihood of widespread exploitation, but targeted attacks against high-value targets remain possible. The lack of availability impact means service disruption is unlikely, but data confidentiality and integrity concerns remain. Organizations in sectors with strict data protection regulations (e.g., finance, healthcare, government) should prioritize mitigation to avoid compliance risks and potential reputational damage.

1. Immediate mitigation involves ensuring all Microsoft Edge installations are updated to the latest version once a patch addressing CVE-2025-53791 is released by Microsoft. 2. Until patches are available, organizations should enforce strict browser usage policies, including disabling or restricting access to risky web content and limiting user privileges to reduce the chance of successful exploitation. 3. Implement network-level protections such as web filtering and intrusion detection systems to detect and block suspicious traffic targeting Edge vulnerabilities. 4. Conduct user awareness training focused on recognizing phishing and social engineering attempts that could trigger the required user interaction for exploitation. 5. Employ endpoint detection and response (EDR) tools to monitor for anomalous browser behavior indicative of exploitation attempts. 6. Review and harden browser security configurations, including disabling unnecessary extensions and features that could be leveraged by attackers. 7. Monitor threat intelligence feeds for updates on exploit availability and adjust defenses accordingly.