CVE-2026-57963

MediumCVSS 6.5

Published: 01/07/2026(UTC)Updated: 01/07/2026(UTC)Translated: 02/07/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.19%

9th percentile — higher than 9% of all known CVEs

Summary

A vulnerability in Thunderbird allows an attacker to send HTML chat messages via Matrix or XMPP, enabling injection of arbitrary styled content, phishing links, and CSS that manipulates the chat UI. This was fixed in Thunderbird 152.0.1 and Thunderbird 140.12.1.

Risk Assessment

The organization is at risk of phishing attacks and UI manipulation, potentially leading to data theft or unauthorized actions.

Recommendation

Immediately update Thunderbird to version 152.0.1 or 140.12.1 to remediate the vulnerability.

Original NVD description (English source)

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.