Description
If Thunderbird was configured to use STARTTLS for an IMAP connection, and an attacker injected IMAP server responses prior to the completion of the STARTTLS handshake, then Thunderbird didn't ignore the injected data. This could have resulted in Thunderbird showing incorrect information, for example the attacker could have tricked Thunderbird to show folders that didn't exist on the IMAP server. This vulnerability affects Thunderbird < 78.12.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | unspecified – < 78.12 | 78.12 |
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.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | thunderbird | 1:78.12.0-1 | — |
| Debian 13 | thunderbird | 1:78.12.0-1 | — |
| Debian 12 | thunderbird | 1:78.12.0-1 | — |
| Debian 10 | thunderbird | 1:78.12.0-1~deb10u1 | DSA-4940-1 |
| Debian 9 | thunderbird | 1:78.12.0-1~deb9u1 | DLA-2711-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | thunderbird | 1:78.13.0+build1-0ubuntu0.20.04.2 | USN-5058-1 |
| Ubuntu 18.04 LTS | thunderbird | 1:78.13.0+build1-0ubuntu0.18.04.1 | USN-5058-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | thunderbird | 78.12.0-3.el8_4 | RHSA-2021:2883 |
| RHEL 7 | thunderbird | 78.12.0-2.el7_9 | RHSA-2021:2881 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.2 EUS | thunderbird | 78.12.0-2.el8_2 | RHSA-2021:2914 |
| RHEL 8.1 EUS | thunderbird | 78.12.0-2.el8_1 | RHSA-2021:2882 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | thunderbird | 78.12.0-3.el8_4 | RLSA-2021:2883 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | MozillaThunderbird | 78.12.0-8.33.1 | SUSE-SU-2021:2458-1 |
| SLES 15 SP2 | MozillaThunderbird | 78.12.0-8.33.1 | SUSE-SU-2021:2458-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaThunderbird | 91.1.1-1.1 | openSUSE-SU-2024:10601-1 |
| openSUSE Leap 15.3 | MozillaThunderbird | 78.12.0-8.33.1 | openSUSE-SU-2021:2458-1 |
| openSUSE Leap 15.2 | MozillaThunderbird | 78.12.0-lp152.2.48.2 | openSUSE-SU-2021:1091-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.23 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.22 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.21 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.20 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.19 | thunderbird | 91.3.2-r0 | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.18 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.17 | thunderbird | 91.3.2-r0 | — |
| Alpine v3.16 | thunderbird | 91.3.2-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 78.13.0-1.amzn2.0.1 | ALAS2-2021-1709 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | thunderbird | 78.12.0-3.0.1.el8_4 | ELSA-2021-2883 |
| Oracle Linux 7 | thunderbird | 78.12.0-2.0.1.el7_9 | ELSA-2021-2881 |
Advisories 15
- RHSA-2021:2881 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-5058-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4940-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2711-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2021:2883 Important: thunderbird security update Rocky Linux Security Advisories · Feb 4, 2026
- SUSE-SU-2021:2458-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:1091-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:2458-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2021:2914 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:2882 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:2883 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- openSUSE-SU-2024:10601-1 MozillaThunderbird-91.1.1-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
- ALAS2-2021-1709 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Sep 15, 2021
- ELSA-2021-2883 Important: thunderbird security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jul 27, 2021
- ELSA-2021-2881 Important: thunderbird security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jul 27, 2021