CVE-2025-13013 is a vulnerability identified in the Document Object Model (DOM): Core & HTML component of Mozilla Firefox, specifically affecting versions earlier than 145 for standard Firefox and earlier than 140.5 and 115.30 for Firefox ESR releases. The vulnerability is characterized as a mitigation bypass, meaning it allows an attacker to circumvent existing security controls designed to prevent exploitation of the DOM. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N) indicates that the attack can be conducted remotely over the network with low attack complexity, requires no privileges, but does require user interaction (such as visiting a malicious website). The scope is changed (S:C), meaning the vulnerability can affect resources beyond the initially vulnerable component. The impact includes limited confidentiality and integrity loss, with no impact on availability. The underlying weakness is related to CWE-288, which involves authentication issues, suggesting the bypass may allow unauthorized actions within the DOM context. No patches or exploits are currently publicly available, but the vulnerability is published and should be addressed promptly. This vulnerability could be exploited by attackers to bypass security mitigations in Firefox's DOM processing, potentially enabling further attacks such as data leakage or manipulation of web content in the browser context.

For European organizations, this vulnerability poses a moderate risk primarily to confidentiality and integrity of data accessed or processed via Firefox browsers. Since Firefox is widely used across Europe in both enterprise and public sectors, especially in government and education, exploitation could lead to unauthorized data exposure or manipulation. The requirement for user interaction means phishing or social engineering could be vectors for exploitation. The scope change implies that an attacker could potentially affect multiple browser components or cross-origin data, increasing the risk in complex web applications. While availability is not impacted, the breach of confidentiality or integrity could lead to compliance issues under GDPR and other data protection regulations, resulting in legal and reputational damage. Organizations relying on Firefox ESR for stability in critical environments may be particularly vulnerable if updates are delayed. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits post-disclosure.

1. Monitor Mozilla security advisories closely and apply Firefox updates to versions 145 or later, or ESR versions 140.5 or later, as soon as patches become available. 2. Until patches are applied, implement strict Content Security Policies (CSP) to limit the execution of untrusted scripts and reduce the risk of malicious content triggering the vulnerability. 3. Educate users about the risks of interacting with untrusted websites or links, emphasizing caution with unsolicited emails or messages that could lead to exploitation. 4. Employ network-level protections such as web filtering and intrusion detection systems to block access to known malicious sites. 5. For organizations using Firefox ESR in critical environments, consider temporary browser alternatives or sandboxing techniques to isolate browser processes. 6. Conduct internal audits of browser usage and ensure that all endpoints are inventoried and updated promptly. 7. Leverage endpoint detection and response (EDR) tools to monitor for suspicious browser behavior indicative of exploitation attempts. 8. Collaborate with IT and security teams to develop incident response plans specific to browser-based attacks.