CVE-2025-8042 in Firefox
Summary
by MITRE • 08/20/2025
Firefox for Android allowed a sandboxed iframe without the `allow-downloads` attribute to start downloads. This vulnerability affects Firefox < 141.
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Analysis
by VulDB Data Team • 08/20/2025
This vulnerability in Firefox for Android represents a sandboxing bypass issue that undermines the browser's security model. The flaw occurs when a sandboxed iframe element lacks the `allow-downloads` attribute yet can still initiate download operations through the browser's download mechanism. This represents a direct violation of the principle of least privilege that governs sandboxed environments where content should be restricted from performing potentially dangerous operations without explicit permission. The vulnerability specifically affects Firefox versions prior to 141, indicating a regression or oversight in the browser's security implementation that allowed unauthorized download initiation from restricted contexts.
The technical exploitation of this vulnerability demonstrates a failure in the browser's permission model for iframe sandboxing. When an iframe is sandboxed, it should be restricted from performing actions that could compromise user security or system integrity. The absence of the `allow-downloads` attribute should prevent download initiation, yet the browser allowed this operation to proceed. This flaw creates a pathway for malicious actors to bypass intended security boundaries and potentially download arbitrary files to the user's device. The vulnerability operates at the intersection of web security policies and browser sandboxing mechanisms, where the expected isolation between trusted and untrusted content is compromised.
The operational impact of this vulnerability extends beyond simple unauthorized downloads and represents a potential vector for more sophisticated attacks. An attacker could leverage this flaw to download malware, phishing tools, or other malicious payloads without user consent or awareness. The sandboxed nature of the iframe means users may not expect such behavior from seemingly restricted content, creating an attack surface that could be exploited for credential theft, system compromise, or data exfiltration. This vulnerability particularly affects mobile users who may be less vigilant about security warnings and more susceptible to social engineering attacks that exploit such browser flaws. The impact is compounded by the fact that this affects the Android version of Firefox, which serves a significant user base and may have different security considerations than desktop implementations.
Mitigation strategies for this vulnerability should focus on immediate user action and browser updates. Users should upgrade to Firefox version 141 or later where this issue has been resolved through proper enforcement of sandboxing restrictions. Security administrators should monitor for exploitation attempts and ensure that all Firefox installations on managed devices are updated. The fix likely involves strengthening the permission checking mechanism for download operations within sandboxed contexts and ensuring that the absence of the `allow-downloads` attribute properly blocks all download initiation attempts. Organizations should also consider implementing network-level monitoring to detect unauthorized download activity that might indicate exploitation attempts. This vulnerability aligns with CWE-250, which addresses improper privilege management in software systems, and represents a specific implementation failure in the ATT&CK framework's privilege escalation techniques. The remediation process should include verifying that all sandboxed content properly enforces security boundaries and that download operations are appropriately restricted based on explicit permissions rather than implicit trust.