Security Advisories

CVE-2021-40835: URL Address Bar Spoofing in F-Secure SAFE Browser for iOS


F-Secure SAFE Browser is vulnerable to URL Address Bar Spoofing


RISK LEVEL:  Medium 

FIX: F-Secure SAFE Browser Version 18.3 and below 

Affected Products

F-Secure SAFE Browser Version 17.9 and below



  • iOS

More Information

An URL Address bar spoofing vulnerability was discovered in Safe Browser for iOS. When user clicks on a specially crafted a malicious URL, if user does not carefully pay attention to url, user may be tricked to think content may be coming from a valid domain, while it comes from another. This is performed by using a very long username part of the url so that user cannot see the domain name. A remote attacker can leverage this to perform url address bar spoofing attack. The fix is, browser no longer shows the user name part in address bar.

Mitigating factors

Exploiting the vulnerability requires the user to click on a specially crafted malicious URL.


F-Secure Corporation would like to thank Narendra Bhati (@imnarendrabhati) for bringing this issue to our attention.