CVE-2025-55030 is a vulnerability identified in Mozilla Firefox for iOS versions earlier than 142, where the browser fails to properly honor the Content-Disposition HTTP header when it is set to 'Attachment'. Normally, this header instructs the browser to download the content rather than display it inline. However, due to this flaw, Firefox for iOS incorrectly renders the content inline, which can be exploited to execute cross-site scripting (XSS) attacks. XSS vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users, potentially leading to data theft, session hijacking, or other malicious activities. The vulnerability is classified under CWE-640 (Weak Password Recovery Mechanism) due to its relation to improper content handling, though the core issue is the incorrect processing of HTTP headers. The CVSS v3.1 base score is 6.1, reflecting a network attack vector with low attack complexity, no privileges required, but requiring user interaction. The scope is changed (S:C), meaning the vulnerability can affect resources beyond the vulnerable component, and it impacts confidentiality and integrity but not availability. No known exploits have been reported in the wild, and no patches are currently linked, indicating that users should monitor Mozilla advisories for updates. The vulnerability primarily affects Firefox for iOS users, which is a subset of the overall Firefox user base, but given the widespread use of iOS devices in Europe, the risk is non-negligible.

For European organizations, this vulnerability poses a moderate risk, particularly for those whose employees or customers use Firefox on iOS devices. Successful exploitation could allow attackers to execute malicious scripts within the browser context, potentially leading to unauthorized access to sensitive information, session hijacking, or manipulation of web content. This is especially critical for sectors handling confidential data such as finance, healthcare, and government services. The vulnerability could be exploited via phishing or malicious websites that trick users into opening crafted links or attachments. Since the flaw involves improper handling of content meant to be downloaded, it undermines the security assumptions of content delivery, increasing the risk of client-side compromise. Although no exploits are currently known, the medium CVSS score and the widespread use of Firefox on iOS in Europe mean that organizations should proactively address this threat to prevent potential data breaches or reputational damage.

1. Update Firefox for iOS to version 142 or later as soon as the patch is released by Mozilla to ensure the vulnerability is remediated. 2. Until an update is available, implement strict content security policies (CSP) on web applications to limit the impact of potential XSS attacks. 3. Educate users about the risks of interacting with unsolicited links or attachments, especially those received via email or messaging apps. 4. Employ mobile device management (MDM) solutions to enforce browser update policies and restrict installation of unapproved apps. 5. Monitor network traffic for unusual activity that could indicate exploitation attempts, such as unexpected inline content rendering or script execution. 6. Encourage the use of alternative browsers with no known vulnerabilities if immediate patching is not feasible. 7. Collaborate with IT security teams to conduct regular security awareness training focusing on phishing and social engineering tactics that could facilitate exploitation.