CVE-2024-10465 is a vulnerability identified in Mozilla Firefox and Thunderbird that allows a clipboard "paste" button to persist across different browser tabs improperly. This behavior can be exploited to conduct spoofing attacks by misleading users into believing that the paste button is contextually relevant when it is not, potentially causing users to paste sensitive or malicious content unintentionally. The flaw affects Firefox versions earlier than 132 and Firefox ESR versions earlier than 128.4, as well as Thunderbird versions earlier than 128.4 and 132. The vulnerability stems from improper UI state management, where the paste button's visibility and context are not correctly reset or isolated between tabs. This can be leveraged by attackers to manipulate the user interface, undermining the integrity of user interactions without requiring any privileges or user interaction. The CVSS v3.1 base score is 7.5, reflecting a high severity due to network attack vector, low attack complexity, no privileges required, and no user interaction needed. The impact is primarily on integrity, as attackers can trick users into pasting unintended content, potentially leading to further exploitation or data manipulation. No known exploits have been reported in the wild yet, but the vulnerability is publicly disclosed and should be addressed promptly. The CWE classification is CWE-290, indicating issues related to authentication or authorization flaws that enable spoofing. Mozilla has not yet published patch links, but updates to the affected products are expected to remediate the issue.

For European organizations, this vulnerability poses a significant risk to the integrity of user interactions within Firefox and Thunderbird, which are widely used in enterprise and government environments. Attackers could exploit this flaw to conduct spoofing attacks that trick users into pasting malicious or unintended data, potentially leading to unauthorized actions, data corruption, or further compromise. Although confidentiality and availability are not directly impacted, the integrity breach can facilitate phishing, social engineering, or malware delivery campaigns. This is particularly concerning for sectors handling sensitive information, such as finance, healthcare, and public administration. The lack of required privileges or user interaction lowers the barrier for attackers, increasing the likelihood of exploitation in targeted attacks. Organizations relying on Firefox ESR versions for stability and security updates must prioritize patching to avoid exposure. The absence of known exploits in the wild provides a window for proactive mitigation, but the public disclosure increases the risk of imminent exploitation attempts.

European organizations should immediately inventory their Firefox and Thunderbird deployments to identify affected versions (Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4 and < 132). They should plan and execute prompt updates to the latest patched versions once Mozilla releases them. Until patches are available, organizations can consider disabling clipboard-related UI features or restricting browser usage policies to limit exposure. Security teams should monitor browser behavior for anomalous or persistent UI elements that could indicate exploitation attempts. User awareness training should emphasize caution when interacting with unexpected clipboard prompts or buttons. Network-level defenses such as web filtering and intrusion detection systems should be tuned to detect suspicious activity related to spoofing or UI manipulation. Additionally, organizations should maintain robust endpoint security solutions to detect and prevent secondary payloads that may result from exploitation. Coordination with Mozilla’s security advisories and rapid deployment of updates will be critical to mitigating this vulnerability.