CVE-2025-10528 is a vulnerability identified in Mozilla Firefox and Thunderbird, specifically affecting versions before Firefox 143 and ESR 140.3. The root cause is an undefined behavior and invalid pointer dereference within the Graphics: Canvas2D component, a critical part of the browser's rendering engine responsible for 2D graphics processing. This flaw enables a sandbox escape, meaning an attacker can break out of the browser's restricted execution environment to execute arbitrary code on the host system. The vulnerability does not require any privileges or user interaction, making it remotely exploitable via crafted web content. The CVSS v3.1 base score is 7.3, indicating high severity, with attack vector as network, low attack complexity, no privileges required, no user interaction, and impacts on confidentiality, integrity, and availability. Although no active exploits have been reported, the presence of such a vulnerability in widely used software like Firefox and Thunderbird poses a significant risk. The CWE-693 classification corresponds to protection mechanism failure, highlighting the failure of sandboxing controls. The vulnerability affects all platforms running the vulnerable versions, and given the critical role of browsers in enterprise environments, exploitation could lead to data breaches, system compromise, or service disruption.

For European organizations, the impact of CVE-2025-10528 could be substantial. Firefox and Thunderbird are widely used across Europe in both public and private sectors, including government agencies, financial institutions, and critical infrastructure operators. Successful exploitation could lead to unauthorized access to sensitive data, disruption of services, and potential lateral movement within networks. Confidentiality could be compromised through data exfiltration, integrity affected by code injection or manipulation, and availability impaired by system crashes or denial-of-service conditions. The lack of required privileges or user interaction lowers the barrier for attackers, increasing the risk of widespread exploitation. Organizations relying heavily on Firefox and Thunderbird without timely patching or compensating controls are particularly vulnerable. The threat is amplified in sectors with high-value targets and sensitive information, such as finance, healthcare, and government.

To mitigate CVE-2025-10528, European organizations should prioritize immediate upgrading of Firefox to version 143 or later and Thunderbird to version 140.3 or later once patches are released. Until patches are available, organizations should implement network-level protections such as blocking access to untrusted or suspicious websites that could host malicious Canvas2D content. Employing endpoint detection and response (EDR) solutions with behavior-based detection can help identify sandbox escape attempts. Restricting browser privileges using application whitelisting and sandbox hardening techniques can reduce exploitation impact. Security teams should monitor browser crash logs and unusual process behaviors indicative of exploitation attempts. User education on avoiding suspicious links and attachments remains important, although user interaction is not required for this exploit. Finally, integrating threat intelligence feeds to stay informed about emerging exploits related to this vulnerability will enable proactive defense.