Name: CVE-2026-57963: Improper Neutralization of Input During Web Page Generation
Creator: Rapid7
Published: 2026-07-01T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-57963, CWE-79, CVSS 6.5, EPSS 0.00306

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.

CVSS Details

CVSS 3.1 Base Score: 6.5
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Debian	—	Upgrade thunderbird	Aug 9, 2026	Aug 9, 2026
Mozilla Thunderbird	—	Upgrade to Mozilla Thunderbird version 140.12.1Upgrade to the latest version of Mozilla Thunderbird	Jul 1, 2026	Jun 30, 2026

Prioritise with Active Threat Intelligence

With curated Threat Intelligence, you can see which vulnerabilities truly put you at risk, prioritize what matters most, and act before attackers do.

Explore Intelligence Hub

MDR Buyer's Guide

Global Threat Landscape Report

Grow your business

CVSS Details

Covered by Rapid7

Prioritise with Active Threat Intelligence