CVE-2025-4919 — Out-of-bounds Read in Mozilla Firefox

CWE-125 — Out-of-bounds ReadCWE-787 — Out-of-bounds Write13 documents9 sources
Severity
8.8HIGHNVD
EPSS
0.3%
top 48.86%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
Mozilla ThunderbirdMozilla Firefox
Timeline
PublishedMay 17
Latest updateJul 22

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitability: 2.8 | Impact: 5.9

Affected Packages3 packages

▶NVDmozilla/firefox116.0 — 128.10.1+2
▶NVDmozilla/thunderbird138.0 — 138.0.2+1
▶Debianmozilla/thunderbird< 1:128.11.0esr-1~deb11u1+3

🔴Vulnerability Details

3
GHSA
GHSA-f333-vhwv-jvmx: An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes↗2025-05-18
▶
OSV
CVE-2025-4919: An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes↗2025-05-17
▶
CVEList
Out-of-bounds access when optimizing linear sums↗2025-05-17
▶

📋Vendor Advisories

8
Ubuntu
Thunderbird vulnerabilities↗2025-07-22
▶
Red Hat
firefox: thunderbird: Out-of-bounds access when optimizing linear sums↗2025-05-17
▶
Debian
CVE-2025-4919: firefox - An attacker was able to perform an out-of-bounds read or write on a JavaScript o...↗2025
▶
Mozilla
Mozilla Foundation Security Advisory 2025-41: CVE-2025-4919↗
▶
Mozilla
Mozilla Foundation Security Advisory 2025-40: CVE-2025-4919↗
▶
CVE-2025-4919 — Out-of-bounds Read in Mozilla Firefox | cvebase