CVE-2026-0818

4.3 MEDIUM
Published: January 28, 2026 Modified: February 04, 2026
View on NVD

Description

When a user explicitly requested Thunderbird to decrypt an inline OpenPGP message that was embedded in a text section of an email that was formatted and styled with HTML and CSS, then the decrypted contents were rendered in a context in which the CSS styles from the outer messages were active. If the user had additionally allowed loading of the remote content referenced by the outer email message, and the email was crafted by the sender using a combination of CSS rules and fonts and animations, then it was possible to extract the secret contents of the email. This vulnerability affects Thunderbird < 147.0.1 and Thunderbird < 140.7.1.

AI Explanation

Get an AI-powered plain-language explanation of this vulnerability and remediation steps.

Login to generate AI explanation

CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1881530
Source: security@mozilla.org
Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-07/
Source: security@mozilla.org
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-08/
Source: security@mozilla.org
Vendor Advisory

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
4.3 / 10.0
EPSS (Exploit Probability)
0.0%
0th percentile
Exploitation Status
Not in CISA KEV

Affected Vendors

mozilla