CVE-2025-4093

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
NISTNIST
6.5 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
mozillaCNA
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CISA-ADPADP
6.5 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 17%
VendorProductVersion
mozillafirefox
𝑥
< 128.10
mozillathunderbird
𝑥
< 128.10.0
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
firefox-esr
bullseye
vulnerable
bullseye (security)
128.11.0esr-1~deb11u1
fixed
bookworm
128.10.0esr-1~deb12u1
fixed
bookworm (security)
128.11.0esr-1~deb12u1
fixed
trixie
128.10.1esr-1
fixed
sid
128.11.0esr-1
fixed
thunderbird
bullseye
vulnerable
bullseye (security)
1:128.11.0esr-1~deb11u1
fixed
bookworm
1:128.10.0esr-1~deb12u1
fixed
bookworm (security)
1:128.10.1esr-1~deb12u1
fixed
trixie
1:128.10.0esr-1
fixed
sid
1:128.11.0esr-1
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
thunderbird
plucky
not-affected
oracular
not-affected
noble
not-affected
jammy
needs-triage
focal
needs-triage
Common Weakness Enumeration
Vulnerability Media Exposure
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/