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OpenAdvisories
High · 7.5 CVE-2026-84641 EUVD-2026-69710GHSA-f2hg-25f8-vgfj

Information disclosure due to malicious IMAP server response

Published Sep 1, 2026 · Updated Sep 2, 2026 · Assigned by mozilla

Description

A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response. Heap contents can ultimately be persisted to prefs.js. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Affected products

VendorProductAffectedFixed
Mozilla Thunderbird — 140.15

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 thunderbird 1:153.2.0esr-1 —
Debian 13 thunderbird 1:140.15.0esr-1~deb13u1 —
Debian 12 thunderbird 1:140.15.0esr-1~deb12u1 —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 thunderbird No fix yet —
Ubuntu 26.04 LTS thunderbird No fix yet —
Ubuntu 24.04 LTS thunderbird No fix yet —
Ubuntu 22.04 LTS thunderbird No fix yet —
ReleasePackageFixed inAdvisory
RHEL 10 thunderbird 140.16.0-1.el10_2 RHSA-2026:73130
RHEL 9 thunderbird 140.16.0-1.el9_8 RHSA-2026:70642
RHEL 8 thunderbird 140.16.0-1.el8_10 RHSA-2026:73971
Show 10 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
RHEL 10.0 EUS thunderbird 140.15.0-1.el10_0 RHSA-2026:77631
RHEL 9.6 EUS thunderbird 140.15.0-1.el9_6 RHSA-2026:80503
RHEL 9.4 E4S thunderbird 140.15.0-1.el9_4 RHSA-2026:77627
RHEL 9.2 E4S thunderbird 140.15.0-1.el9_2 RHSA-2026:77632
RHEL 8.8 TUS thunderbird 140.16.0-1.el8_8 RHSA-2026:81912
RHEL 8.8 E4S thunderbird 140.16.0-1.el8_8 RHSA-2026:81912
RHEL 8.6 EUS Long Life thunderbird 140.16.0-1.el8_6 RHSA-2026:81913
RHEL 8.6 AUS thunderbird 140.16.0-1.el8_6 RHSA-2026:81913
RHEL 8.4 EUS Long Life thunderbird 140.16.0-1.el8_4 RHSA-2026:82122
RHEL 8.4 AUS thunderbird 140.16.0-1.el8_4 RHSA-2026:82122

AlmaLinux

Errata ↗
ReleasePackageFixed inAdvisory
AlmaLinux 10 thunderbird 140.16.0-1.el10_2.alma.1 ALSA-2026:73130
AlmaLinux 9 thunderbird 140.16.0-1.el9_8.alma.1 ALSA-2026:70642
AlmaLinux 8 thunderbird 140.16.0-1.el8_10.alma.1 ALSA-2026:73971

Rocky Linux

Errata ↗
ReleasePackageFixed inAdvisory
Rocky Linux 10 thunderbird 140.16.0-1.el10_2 RLSA-2026:73130
Rocky Linux 9 thunderbird 140.16.0-1.el9_8 RLSA-2026:70642
Rocky Linux 8 thunderbird 140.16.0-1.el8_10 RLSA-2026:73971
ReleasePackageFixed inAdvisory
SLES 15 SP7 MozillaThunderbird 153.2.0-150400.13.3.1 SUSE-SU-2026:4268-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed MozillaThunderbird 140.15.0-1.1 openSUSE-SU-2026:11678-1

Amazon Linux

ReleasePackageFixed inAdvisory
Amazon Linux 2 thunderbird 140.16.0-1.amzn2.0.1 ALAS2-2026-3952

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 10 thunderbird 140.16.0-1.0.1.el10_2 ELSA-2026-73130
Oracle Linux 9 thunderbird 140.16.0-1.0.1.el9_8 ELSA-2026-70642
Oracle Linux 8 thunderbird 140.16.0-1.0.1.el8_10 ELSA-2026-73971

Advisories 23

References