Use After Free in Mozilla Firefox

CVE-2025-3028

JavaScript code running while transforming a document with the XSLTProcessor could lead to a use-after-free. This vulnerability was fixed in Firefox 137, Firefox ESR 115.22, Firefox ESR 128.9, Thunderbird 137, and Thunderbird 128.9.

Vulnerability class: Use-After-Free

EPSS: 0.008 (53.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

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

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-3028?
CVE-2025-3028 is a medium-severity vulnerability in Mozilla Firefox, classified under Use After Free. CVSS score: 6.5/10. Published 2025-04-01.
How severe is CVE-2025-3028?
Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2025-3028 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.