What’s Vulnerable › Vulnerabilities

CVE-2021-44751: F-Secure SAFE Browser vulnerable to USSD attacks

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-03-25 · updated 2026-06-17
• Weakness: CWE-276

Description

A vulnerability affecting F-Secure SAFE browser was discovered. A maliciously crafted website attached with USSD code in JavaScript or iFrame can trigger dialer application from F-Secure browser which can be exploited by an attacker to send unwanted USSD messages or perform unwanted calls. In most modern Android OS, dialer application will require user interaction, however, some older Android OS may not need user interaction.

Affected products

• F-Secure SAFE Browser for Android Version 18.5: before 18.5 — fixed in 18.5

How to fix

Upgrade to a fixed version: F-Secure SAFE Browser for Android Version 18.5 18.5. Check the vendor advisory for mitigations.

References

• https://www.f-secure.com/en/business/programs/vulnerability-reward-program/hall-of-fame
• https://www.f-secure.com/en/business/programs/vulnerability-reward-program/hall-of-fame

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