CVE-2025-4919
8.8
HIGH
CVSS 3.1
EPSS 0.28%
Description
An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes. This vulnerability was fixed in Firefox 138.0.4, Firefox ESR 128.10.1, Firefox ESR 115.23.1, Thunderbird 128.10.2, and Thunderbird 138.0.2.
How to fix CVE-2025-4919
To remediate CVE-2025-4919, upgrade the affected package to a fixed version below.
- Debian/firefox-esr—upgrade to 128.10.1esr-1~deb11u1 or later
- —upgrade to 1:128.11.0esr-1~deb11u1 or later
Is CVE-2025-4919 being exploited?
Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 128.10.1esr-1~deb11u1
- from 0, < 1:128.11.0esr-1~deb11u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |