Fake Apple login prompt in F-Secure SAFE browser for iOS

published 2021-08-05 5y ago modified 2026-06-17 4mo ago also EUVD-2021-20280

cvss: 3.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.8%; EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits: 0; none known

Showing the legitimate URL in the address bar while loading the content from other domain. This makes the user believe that the content is served by a legit domain. Exploiting the vulnerability requires the user to click on a specially crafted, seemingly legitimate URL containing an embedded malicious redirect while using F-Secure Safe Browser for iOS.

Patch / fix

fixed in 1

F-Secure F-Secure Mobile Security 18.4x

Is CVE-2021-33596 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

0.80% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.1	3.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
NVD	3.1	4.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N
NVD	2.0	3.5	AV:N/AC:M/Au:S/C:N/I:P/A:N

Affected products

F-Secure F-Secure Mobile Security

Classification

Weakness

CWE-1021 Improper Restriction of Rendered UI Layers or Frames

References

f-secure.com /en/business/programs/vulnerability-reward-program/hall-of-fame
vendor-advisory
f-secure.com /en/business/support-and-downloads/security-advisories
vendor-advisory
f-secure.com /en/business/support-and-downloads/security-advisories/cve-2021-33596
vendor-advisory

Sources

CVE List CVE-2021-33596
NVD CVE-2021-33596

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.