CVE-2025-4093

EUVD-2025-12642
Memory safety bug present in Firefox ESR 128.9, and Thunderbird 128.9. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 128.10 and Thunderbird < 128.10.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
8.1 HIGH
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA-ADPADP
8.1 HIGH
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 61%
Affected Products (NVD)
VendorProductVersion
mozillafirefox
𝑥
< 128.10
mozillathunderbird
𝑥
< 128.10.0
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
firefox-esr
bookworm
128.14.0esr-1~deb12u1
fixed
bookworm (security)
140.8.0esr-1~deb12u1
fixed
bullseye
vulnerable
bullseye (security)
140.8.0esr-1~deb11u1
fixed
forky
140.8.0esr-1
fixed
sid
140.8.0esr-1
fixed
trixie
140.4.0esr-1~deb13u1
fixed
trixie (security)
140.8.0esr-1~deb13u1
fixed
thunderbird
bookworm
1:140.6.0esr-1~deb12u1
fixed
bookworm (security)
1:140.8.0esr-1~deb12u1
fixed
bullseye
vulnerable
bullseye (security)
1:140.8.0esr-1~deb11u1
fixed
forky
1:140.8.0esr-1
fixed
sid
1:140.8.0esr-1
fixed
trixie
1:140.6.0esr-1~deb13u1
fixed
trixie (security)
1:140.8.0esr-1~deb13u1
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
thunderbird
focal
dne
jammy
Fixed 1:128.12.0+build1-0ubuntu0.22.04.1
released
noble
not-affected
oracular
not-affected
plucky
not-affected
Common Weakness Enumeration
References
https://bugzilla.mozilla.org/show_bug.cgi?id=1894100
https://www.mozilla.org/security/advisories/mfsa2025-29/
https://www.mozilla.org/security/advisories/mfsa2025-32/
https://lists.debian.org/debian-lts-announce/2025/05/msg00024.html