CVE-2026-14899

EUVD-2026-47773
The code to parse MIME headers for display when forwarding a message (if the setting to view all headers was enabled) had an off-by-one error, allowing a single byte to be read from the memory after the buffer for the headers, and potentially crashing Thunderbird. This vulnerability was fixed in Thunderbird 153 and Thunderbird 140.13.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
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: 19.44%
Affected Products (NVD)
VendorProductVersion
mozillathunderbird_esr
𝑥
< 140.13.0
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
thunderbird
bookworm
vulnerable
bookworm (security)
1:140.14.0esr-1~deb12u1
fixed
bullseye
vulnerable
bullseye (security)
1:140.14.0esr-1~deb11u1
fixed
forky
1:140.14.0esr-1
fixed
sid
1:140.14.0esr-1
fixed
trixie
vulnerable
trixie (security)
1:140.14.0esr-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
140.13.0-150200.8.280.1
fixed
suse enterprise sap 15 SP7
140.13.0-150200.8.280.1
fixed
suse enterprise server 15 SP7
140.13.0-150200.8.280.1
fixed
suse enterprise workstation 15 SP7
140.13.0-150200.8.280.1
fixed
MozillaThunderbird-translations-common
suse enterprise desktop 15 SP7
140.13.0-150200.8.280.1
fixed
suse enterprise sap 15 SP7
140.13.0-150200.8.280.1
fixed
suse enterprise server 15 SP7
140.13.0-150200.8.280.1
fixed
suse enterprise workstation 15 SP7
140.13.0-150200.8.280.1
fixed
MozillaThunderbird-translations-other
suse enterprise desktop 15 SP7
140.13.0-150200.8.280.1
fixed
suse enterprise sap 15 SP7
140.13.0-150200.8.280.1
fixed
suse enterprise server 15 SP7
140.13.0-150200.8.280.1
fixed
suse enterprise workstation 15 SP7
140.13.0-150200.8.280.1
fixed
Red Hat logo
Red Hat Enterprise Linux Releases
Red Hat Product
Release
thunderbird
RHEL 9
0:140.13.0-1.el9_8
fixed
Amazon Linux logo
Amazon Linux Releases
Amazon Package
Release
thunderbird
Amazon Linux 2
0:140.13.0-1.amzn2.0.1
fixed