What is CVE-2025-55028?

CVE-2025-55028 is a medium-severity vulnerability in Mozilla Firefox, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2025-08-19.

How severe is CVE-2025-55028?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Resource exhaustion in Mozilla Firefox

CVE-2025-55028

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.

Vulnerability class: DoS (Denial of Service)

Published 2025-08-19 · last modified 2026-10-05.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.002 (12.0th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 12th percentile — 12.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Mozilla Firefox
Mozilla Firefox For iOS — versions 142

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

References

bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)
www.mozilla.org/security/advisories/mfsa2025-68/ (Vendor Advisory)

Frequently asked questions

What is CVE-2025-55028?: CVE-2025-55028 is a medium-severity vulnerability in Mozilla Firefox, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2025-08-19.
How severe is CVE-2025-55028?: Medium severity. CVSS v3 base score is 6.5 out of 10.