CVE-2025-11710 is a critical security vulnerability discovered in Mozilla Firefox and Thunderbird that involves a flaw in the handling of inter-process communication (IPC) messages between the web content process and the privileged browser process. Specifically, a compromised web process can send crafted malicious IPC messages that cause the privileged browser process to inadvertently disclose blocks of its memory to the attacker-controlled process. This memory disclosure can expose sensitive information such as user credentials, session tokens, or other confidential data stored in memory. The vulnerability affects Firefox versions earlier than 144, Firefox ESR versions earlier than 115.29 and 140.4, and Thunderbird versions earlier than 144 and 140.4. The CVSS v3.1 base score is 9.8, reflecting a critical severity level due to the vulnerability's network attack vector (no physical or local access required), low attack complexity, no privileges required, and no user interaction needed. The scope is unchanged, but the impact on confidentiality, integrity, and availability is high, as an attacker can leak sensitive memory contents and potentially manipulate browser behavior. Although no public exploits have been reported yet, the vulnerability represents a significant risk given the widespread use of Firefox and Thunderbird. The root cause relates to improper validation or sanitization of IPC messages, categorized under CWE-200 (Exposure of Sensitive Information).

For European organizations, the impact of CVE-2025-11710 is substantial due to the widespread use of Firefox and Thunderbird in both private and public sectors. Successful exploitation could lead to unauthorized disclosure of sensitive information, including credentials, personal data, and corporate secrets, undermining confidentiality. Integrity and availability may also be compromised if attackers leverage leaked memory data to escalate privileges or execute further attacks. Sectors such as finance, government, healthcare, and critical infrastructure are particularly vulnerable due to the sensitive nature of their data and reliance on secure communications. The vulnerability could facilitate espionage, data breaches, and disruption of services, potentially violating GDPR and other data protection regulations, leading to legal and financial repercussions. The lack of required privileges or user interaction lowers the barrier for attackers, increasing the likelihood of exploitation in targeted or opportunistic attacks.

1. Apply official patches from Mozilla immediately once they are released for Firefox and Thunderbird versions affected by this vulnerability. 2. Until patches are available, consider deploying network-level controls to restrict access to Firefox and Thunderbird IPC channels, if feasible. 3. Use application sandboxing and process isolation features to limit the impact of compromised web processes. 4. Monitor browser process behavior and IPC message traffic for anomalies indicative of exploitation attempts. 5. Educate users about the importance of keeping browsers updated and avoiding untrusted websites that could host malicious content. 6. Employ endpoint detection and response (EDR) tools capable of detecting suspicious inter-process communications or memory access patterns. 7. For organizations with strict security requirements, consider temporarily restricting the use of affected versions or switching to alternative browsers until patches are applied. 8. Review and enhance incident response plans to quickly address potential exploitation scenarios involving browser memory disclosure.