HOMEVULNERABILITIESCVE-2021-33596
MEDIUM

CVE-2021-33596

CWE-1021Published: August 5, 2021· Updated: Jun 17, 2026

4.1
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2021-33596 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.Low
User InteractionRequired
ScopeChanged
Impact
ConfidentialityNone
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N

Affected Vendors & Products

f-secure1 product(s)
safe
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

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

All References (6)

→
https://www.f-secure.com/en/business/programs/vulnerability-reward-program/hall-of-fameVendor Advisory
→
https://www.f-secure.com/en/business/support-and-downloads/security-advisoriesVendor Advisory
→
https://www.f-secure.com/en/business/support-and-downloads/security-advisories/cve-2021-33596Vendor Advisory
→
https://www.f-secure.com/en/business/programs/vulnerability-reward-program/hall-of-fameVendor Advisory
→
https://www.f-secure.com/en/business/support-and-downloads/security-advisoriesVendor Advisory
→
https://www.f-secure.com/en/business/support-and-downloads/security-advisories/cve-2021-33596Vendor Advisory

Quick Facts

CVE IDCVE-2021-33596
CVSS Score4.1 / 10
SeverityMEDIUM
WeaknessCWE-1021
CISA KEVNo
Affected1 vendor(s)
PublishedAug 5, 2021

Related CVEs (CWE-1021)

CVE-2021-23274
9.8
CVE-2016-2496
9.8
CVE-2021-43048
9.8
CVE-2021-21111
9.6
CVE-2021-21132
9.6
CVE-2023-41897
9.6

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-33596 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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