CVE-2026-84640

EUVD-2026-69709
A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
mozillaCNA
7.5 HIGH
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 16.87%
Affected Products (NVD)
VendorProductVersion
mozillathunderbird
𝑥
< 140.15.0
mozillathunderbird
141.0 ≤
𝑥
< 153.2.0
𝑥
= Vulnerable software versions
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
mozillathunderbird
154.0 ≤
𝑥
< 155.0
CNA
mozillathunderbird_esr
𝑥
< 140.15.0
CNA
mozillathunderbird_esr
141.0 ≤
𝑥
< 153.2.0
CNA
Debian logo
Debian Releases
Debian Product
Codename
thunderbird
bookworm
vulnerable
bookworm (security)
1:140.17.0esr-1~deb12u1
fixed
forky
1:153.4.0esr-1
fixed
sid
1:153.4.0esr-1
fixed
trixie
vulnerable
trixie (security)
1:140.17.0esr-1~deb13u1
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
thunderbird
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
openSUSE logo
openSUSE / SLES Releases
openSUSE Product
Release
MozillaThunderbird
suse enterprise desktop 15 SP7
153.2.0-150400.13.3.1
fixed
suse enterprise sap 15 SP7
153.2.0-150400.13.3.1
fixed
suse enterprise server 15 SP7
153.2.0-150400.13.3.1
fixed
suse enterprise workstation 15 SP7
153.2.0-150400.13.3.1
fixed
MozillaThunderbird-translations-common
suse enterprise desktop 15 SP7
153.2.0-150400.13.3.1
fixed
suse enterprise sap 15 SP7
153.2.0-150400.13.3.1
fixed
suse enterprise server 15 SP7
153.2.0-150400.13.3.1
fixed
suse enterprise workstation 15 SP7
153.2.0-150400.13.3.1
fixed
MozillaThunderbird-translations-other
suse enterprise desktop 15 SP7
153.2.0-150400.13.3.1
fixed
suse enterprise sap 15 SP7
153.2.0-150400.13.3.1
fixed
suse enterprise server 15 SP7
153.2.0-150400.13.3.1
fixed
suse enterprise workstation 15 SP7
153.2.0-150400.13.3.1
fixed
Red Hat logo
Red Hat Enterprise Linux Releases
Red Hat Product
Release
thunderbird
RHEL 9
0:140.16.0-1.el9_8
fixed
Amazon Linux logo
Amazon Linux Releases
Amazon Package
Release
thunderbird
Amazon Linux 2
0:140.16.0-1.amzn2.0.1
fixed