Description
Thunderbird did not escape attribute values when serializing outgoing XMPP stanzas. Because values from incoming requests were echoed back in automatic replies, a remote XMPP user could send a crafted request that caused Thunderbird to inject arbitrary stanzas into the user's connection, which the server would then process as if sent by the user. This could be used to send messages or change contact and subscription settings on behalf of the user, without any interaction. This bug only affects Thunderbird's chat feature with XMPP accounts. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Thunderbird | — | 153.5.1 |
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 | No fix yet | — |
| Debian 13 | thunderbird | 1:153.5.1esr-1~deb13u1 | — |
| Debian 12 | thunderbird | 1:153.5.1esr-1~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 | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | MozillaThunderbird | 153.5.1-1.1 | openSUSE-SU-2026:12224-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | thunderbird | 153.5.1-1.amzn2.0.1 | ALAS2-2026-4057 |
Advisories 3
- WID-SEC-2026-4064 Mozilla Produkte (Thunderbird, Firefox ESR und Firefox): Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- ALAS2-2026-4057 Important: thunderbird security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Nov 2, 2026
- openSUSE-SU-2026:12224-1 MozillaThunderbird-153.5.1-1.1 on GA media SUSE / openSUSE Security Updates · Oct 23, 2026