Description
When loading the shared library that provides the OTR protocol implementation, Thunderbird will initially attempt to open it using a filename that isn't distributed by Thunderbird. If a computer has already been infected with a malicious library of the alternative filename, and the malicious library has been copied to a directory that is contained in the search path for executable libraries, then Thunderbird will load the incorrect library. This vulnerability affects Thunderbird < 78.9.1.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | unspecified – < 78.9.1 | 78.9.1 |
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 | 1:78.10.0-1 | — |
| Debian 13 | thunderbird | 1:78.10.0-1 | — |
| Debian 12 | thunderbird | 1:78.10.0-1 | — |
| Debian 10 | thunderbird | 1:78.10.0-1~deb10u1 | DSA-4897-1 |
| Debian 9 | thunderbird | 1:78.10.0-1~deb9u1 | DLA-2632-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | thunderbird | 1:78.11.0+build1-0ubuntu0.20.04.2 | USN-4995-1 |
| Ubuntu 18.04 LTS | thunderbird | 1:78.11.0+build1-0ubuntu0.18.04.2 | USN-4995-2 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | thunderbird | 78.9.1-1.el8_3 | RHSA-2021:1193 |
| RHEL 7 | thunderbird | 78.9.1-1.el7_9 | RHSA-2021:1192 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.2 EUS | thunderbird | 78.9.1-1.el8_2 | RHSA-2021:1201 |
| RHEL 8.1 EUS | thunderbird | 78.9.1-1.el8_1 | RHSA-2021:1190 |
Advisories 8
- RHSA-2021:1192 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-4995-2 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- USN-4995-1 thunderbird vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4897-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2632-1 thunderbird - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RHSA-2021:1201 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:1193 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- RHSA-2021:1190 Red Hat Security Advisory: thunderbird security update Red Hat Security Advisories (RHSA) · Nov 22, 2025