- 3.5LowCVSS base score
- 0.80%Exploitation in 30 daysEPSS · top 43% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By F-SecureUS
- 2 months later
· 2 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| F-SecureUSCNA (assigner) | 3.1 | Low3.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium4.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.80% · top 43% of all CVEs (11 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 3.5.
Affected products
F-Secure · F-Secure Mobile Security
- affected 18.3x – < 18.4x
What to do
Solution: Upgrade to version 18.4.x or newer from the App Store
References
References3
- https://www.f-secure.com/en/business/programs/vulnerability-reward-program/hall-of-fame (opens in a new tab)x_refsource_MISCx_transferred
- https://www.f-secure.com/en/business/support-and-downloads/security-advisories (opens in a new tab)x_refsource_MISCx_transferred
- https://www.f-secure.com/en/business/support-and-downloads/security-advisories/cve-2021-33596 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-20280 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-33596)Record last updated .