HOMEVULNERABILITIESCVE-2021-40835
MEDIUM

CVE-2021-40835

NVD-CWE-OtherPublished: December 16, 2021· Updated: Jun 17, 2026

4.3
CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2021-40835 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionRequired
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/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/programs/vulnerability-reward-program/hall-of-fame
ADVISORYhttps://www.f-secure.com/en/business/support-and-downloads/security-advisories

All References (4)

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

Quick Facts

CVE IDCVE-2021-40835
CVSS Score4.3 / 10
SeverityMEDIUM
WeaknessNVD-CWE-Other
CISA KEVNo
Affected1 vendor(s)
PublishedDec 16, 2021

Related CVEs (NVD-CWE-Other)

CVE-2005-2023
10.0
CVE-2005-0771
10.0
CVE-2005-3666
10.0
CVE-2005-1897
10.0
CVE-2005-1208
10.0
CVE-1999-0489
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-40835 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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