medium6.5
CVE-2026-57963
An attacker who can send HTML chat messages (via Matrix or XMPP) can inject arbitrary styled content, phishing links, and CSS that manipulates the chat UI.
Impact
An attacker who can send HTML chat messages (via Matrix or XMPP) can inject arbitrary styled content, phishing links, and CSS that manipulates the chat UI. This vulnerability was fixed in Thunderbird 152.0.1 and Thunderbird 140.12.1.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Mozilla | Thunderbird | before 140.12.1 before 152.0.1 |