CVE-2025-10528 is a security vulnerability identified in the Graphics: Canvas2D component of Mozilla Firefox versions prior to 143 and Firefox ESR versions prior to 140.3. The vulnerability arises from undefined behavior caused by an invalid pointer within the Canvas2D rendering subsystem. This flaw can potentially be exploited to escape the browser's sandbox environment, which is designed to isolate web content and prevent malicious code from affecting the host system. The sandbox escape implies that an attacker could execute arbitrary code outside the restricted browser context, thereby gaining elevated privileges on the victim's machine. Although no known exploits are currently reported in the wild, the nature of the vulnerability suggests that it could be leveraged by attackers to compromise user confidentiality, integrity, and system availability. The lack of a CVSS score indicates that the vulnerability is newly disclosed and has not yet undergone formal severity assessment. The vulnerability affects a widely used browser component responsible for rendering 2D graphics, which is commonly used by web applications, making the attack surface broad. Exploitation would likely require the victim to visit a malicious or compromised website that triggers the invalid pointer behavior in the Canvas2D component. Given the sandbox escape capability, the impact could extend beyond typical browser-based attacks to full system compromise.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Mozilla Firefox across both enterprise and consumer environments. A successful sandbox escape could allow attackers to bypass browser security controls, leading to potential data breaches, installation of persistent malware, or lateral movement within corporate networks. Sensitive information handled within browsers, such as credentials, personal data, or confidential documents accessed via web applications, could be exposed. The vulnerability could also facilitate targeted attacks against high-value entities, including government agencies, financial institutions, and critical infrastructure operators that rely on Firefox for secure web access. Additionally, the ability to execute code outside the sandbox increases the risk of ransomware deployment or espionage activities. The absence of known exploits currently provides a window for proactive mitigation, but the potential for rapid weaponization means organizations must act swiftly to reduce exposure.

European organizations should prioritize updating Mozilla Firefox to version 143 or later, and Firefox ESR to version 140.3 or later, as soon as patches become available. Until updates are applied, organizations should consider implementing network-level protections such as web filtering to block access to untrusted or suspicious websites that could host exploit code. Employing endpoint detection and response (EDR) solutions capable of monitoring for anomalous process behavior related to sandbox escapes can provide early warning of exploitation attempts. Security teams should also review browser configuration policies to disable or restrict Canvas2D usage where feasible, or employ browser isolation technologies to contain potential exploits. User awareness training should emphasize the risks of visiting untrusted websites and the importance of timely software updates. Finally, organizations should monitor Mozilla security advisories and threat intelligence feeds for any emerging exploit reports related to this vulnerability.