CVE-2026-57963

medium

Description

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.

References

https://www.mozilla.org/security/advisories/mfsa2026-64/

https://www.mozilla.org/security/advisories/mfsa2026-63/

https://bugzilla.mozilla.org/show_bug.cgi?id=2042910

Details

Source: Mitre, NVD

Published: 2026-07-01

Updated: 2026-07-01

Risk Information

CVSS v2

Base Score: 5

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N