CVE-2026-57963

Published: Jul 1, 2026Modified: Jul 6, 2026

6.5

Vector

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

Exploitability: 3.9 / Impact: 2.5

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

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.

Affected (2)

Products: Mozilla: Thunderbird

Mozilla

1 product

Thunderbird

Configuration A

2 vulnerable

Vulnerable Software	Affected Versions
Mozilla Thunderbird	Before 152.0.1
Mozilla Thunderbird	Before 140.12.1

Related CWEs

CWE-79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

References (3)

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

Source: security@mozilla.org

Permissions Required

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

Source: security@mozilla.org

Vendor Advisory

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

Source: security@mozilla.org

Vendor Advisory

Timeline

No history available yet.