Description
A malicious LDAP server, which a Thunderbird user is configured to query for address-book autocomplete, can stash arbitrarily large amounts of attacker-supplied data into the Thunderbird LDAP client until it crashes due to memory exhaustion. This vulnerability was fixed in Thunderbird 152.0.1 and Thunderbird 140.12.1.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | — | 140.12.1 |
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 | 1:140.13.0esr-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 25.10 | thunderbird | No fix yet | — |
| Ubuntu 24.04 LTS | thunderbird | No fix yet | — |
| Ubuntu 22.04 LTS | thunderbird | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaThunderbird | 140.12.1-1.1 | openSUSE-SU-2026:11164-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 140.13.0-1.amzn2.0.1 | ALAS2-2026-3868 |
Advisories 3
- WID-SEC-2026-2178 Mozilla Thunderbird: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 17, 2026
- ALAS2-2026-3868 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Aug 17, 2026
- openSUSE-SU-2026:11164-1 MozillaThunderbird-140.12.1-1.1 on GA media SUSE / openSUSE Security Updates · Jul 2, 2026