CVE-2026-57963
thunderbird: Chat UI manipulation by injection
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · July 1, 2026
Updated · November 5, 2026
Description
A flaw was found in Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue: 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.
Statement
Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 7.5CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE-79 · Improper Neutralization of Input During Web Page Generation