What’s Vulnerable › Vulnerabilities

CVE-2025-55028: JavaScript alerts could impede UI interaction or allow denial of service attacks

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-08-19 · updated 2026-10-05
• Weakness: CWE-400

Description

Malicious scripts utilizing repetitive JavaScript alerts could prevent client user interaction in some scenarios and allow for denial of service attacks. This vulnerability was fixed in Firefox for iOS 142.

Affected products

• Mozilla Firefox: before 142.0 — fixed in 142.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 142.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1850240
• https://www.mozilla.org/security/advisories/mfsa2025-68/

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