CVE-2025-55032 is a vulnerability identified in Mozilla Focus for iOS, a privacy-focused web browser. The issue arises because the browser does not correctly honor the Content-Disposition HTTP header when it is set to 'Attachment'. Normally, this header instructs the browser to treat the content as a downloadable file rather than rendering it inline. However, affected versions of Focus for iOS (versions prior to 142) incorrectly display such content inline. This improper handling can be exploited by attackers to perform cross-site scripting (XSS) attacks. Specifically, an attacker can craft a malicious web page or link that delivers a payload disguised as an attachment but rendered inline, allowing the execution of arbitrary scripts within the browser context. The vulnerability is classified under CWE-601 (Open Redirect), indicating that it involves improper handling of URLs or content disposition leading to security bypass. The CVSS v3.1 base score is 6.1 (medium severity), reflecting that the attack vector is network-based (remote), requires no privileges, but does require user interaction (clicking a malicious link). The scope is changed (S:C), meaning the vulnerability can affect resources beyond the initially vulnerable component. The impact affects confidentiality and integrity but not availability. No patches or known exploits are currently documented, but the vulnerability poses a risk to users who might be tricked into interacting with malicious content. The issue is particularly relevant for iOS users of Mozilla Focus, a browser favored for privacy, potentially undermining user trust and security.

For European organizations, this vulnerability could lead to unauthorized script execution within the browser context, potentially exposing sensitive information such as session tokens, personal data, or corporate credentials. This could facilitate further attacks like session hijacking, phishing, or lateral movement within enterprise environments. Since Mozilla Focus is used primarily on iOS devices, the impact is limited to organizations with employees or users who utilize this browser. The vulnerability could undermine privacy guarantees and data integrity, especially in sectors handling sensitive or regulated data such as finance, healthcare, and government. Although no active exploits are reported, the medium severity rating and the requirement for user interaction mean that targeted phishing campaigns could leverage this vulnerability. The inability to properly handle Content-Disposition headers may also affect compliance with data protection regulations if sensitive data is exposed or manipulated. Overall, the threat could degrade trust in secure browsing environments and increase the attack surface for social engineering attacks.

European organizations should ensure that all iOS devices running Mozilla Focus are updated to version 142 or later once the patch is released. Until then, users should be educated about the risks of clicking on untrusted links, especially those that prompt downloads or attachments. Deploy mobile device management (MDM) solutions to enforce browser updates and restrict installation of unapproved applications. Implement network-level protections such as web filtering and intrusion prevention systems to block access to known malicious URLs or domains that could exploit this vulnerability. Consider deploying endpoint detection and response (EDR) tools capable of detecting anomalous script execution behaviors on iOS devices. Additionally, organizations should review their incident response plans to include scenarios involving browser-based XSS attacks and conduct phishing awareness training tailored to this threat. Monitoring for unusual browser activity and logs can help detect exploitation attempts early. Finally, coordinate with Mozilla for timely patch deployment and verify the integrity of browser updates.