Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | — | 140.13 |
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 | 1:140.13.0esr-1 | — |
| Debian 13 | thunderbird | 1:140.13.0esr-2~deb13u1 | — |
| Debian 12 | thunderbird | 1:140.13.0esr-2~deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| 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 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | thunderbird | 140.13.0-1.el10_2 | RHSA-2026:49621 |
| RHEL 9 | thunderbird | 140.13.0-1.el9_8 | RHSA-2026:49921 |
| RHEL 8 | thunderbird | 140.13.0-1.el8_10 | RHSA-2026:49922 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.0 EUS | thunderbird | 140.13.0-1.el10_0 | RHSA-2026:53445 |
| RHEL 9.6 EUS | thunderbird | 140.13.0-1.el9_6 | RHSA-2026:53446 |
| RHEL 9.4 E4S | thunderbird | 140.13.0-1.el9_4 | RHSA-2026:53444 |
| RHEL 9.2 E4S | thunderbird | 140.13.0-1.el9_2 | RHSA-2026:53475 |
| RHEL 8.8 TUS | thunderbird | 140.13.0-1.el8_8 | RHSA-2026:53454 |
| RHEL 8.8 E4S | thunderbird | 140.13.0-1.el8_8 | RHSA-2026:53454 |
| RHEL 8.6 EUS Long Life | thunderbird | 140.13.0-1.el8_6 | RHSA-2026:53453 |
| RHEL 8.6 AUS | thunderbird | 140.13.0-1.el8_6 | RHSA-2026:53453 |
| RHEL 8.4 EUS Long Life | thunderbird | 140.13.0-1.el8_4 | RHSA-2026:53455 |
| RHEL 8.4 AUS | thunderbird | 140.13.0-1.el8_4 | RHSA-2026:53455 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | thunderbird | 140.13.0-1.el10_2.alma.1 | ALSA-2026:49621 |
| AlmaLinux 9 | thunderbird | 140.13.0-1.el9_8.alma.1 | ALSA-2026:49921 |
| AlmaLinux 8 | thunderbird | 140.13.0-1.el8_10.alma.1 | ALSA-2026:49922 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | thunderbird | 140.13.0-1.el10_2 | RLSA-2026:49621 |
| Rocky Linux 9 | thunderbird | 140.13.0-1.el9_8 | RLSA-2026:49921 |
| Rocky Linux 8 | thunderbird | 140.13.0-1.el8_10 | RLSA-2026:49922 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | MozillaThunderbird | 140.13.0-150200.8.280.1 | SUSE-SU-2026:4268-1, SUSE-SU-2026:3546-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaThunderbird | 140.13.0-1.1 | openSUSE-SU-2026:11359-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 140.13.0-1.amzn2.0.1 | ALAS2-2026-3868 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | thunderbird | 140.13.0-1.0.1.el10_2 | ELSA-2026-49621 |
| Oracle Linux 9 | thunderbird | 140.13.0-1.0.1.el9_8 | ELSA-2026-49921 |
| Oracle Linux 8 | thunderbird | 140.13.0-1.0.1.el8_10 | ELSA-2026-49922 |
Advisories 24
- WID-SEC-2026-2458 Mozilla Firefox und Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 8, 2026
- ALSA-2026:49921 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:49621 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:49922 Important: thunderbird security update AlmaLinux Security Advisories · Oct 29, 2026
- SUSE-SU-2026:4268-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Sep 19, 2026
- RHSA-2026:53444 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2026:53445 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2026:53446 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2026:53453 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2026:53454 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2026:53455 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2026:53475 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2026:49921 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2026:49922 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- RHSA-2026:49621 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Sep 9, 2026
- ALAS2-2026-3868 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Aug 17, 2026
- SUSE-SU-2026:3546-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Aug 11, 2026
- RLSA-2026:49921 Important: thunderbird security update Rocky Linux Security Advisories · Aug 6, 2026
- RLSA-2026:49621 Important: thunderbird security update Rocky Linux Security Advisories · Aug 6, 2026
- RLSA-2026:49922 Important: thunderbird security update Rocky Linux Security Advisories · Aug 6, 2026
- ELSA-2026-49922 Important: thunderbird security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Aug 4, 2026
- ELSA-2026-49921 Important: thunderbird security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Aug 4, 2026
- ELSA-2026-49621 Important: thunderbird security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Aug 3, 2026
- openSUSE-SU-2026:11359-1 MozillaThunderbird-140.13.0-1.1 on GA media SUSE / openSUSE Security Updates · Jul 25, 2026