CVE-2026-0818
Medium · 4.3CVSS
4.3
EPSS
0.2%
Published
Jan 28, 2026
CISA due date
—
The record
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 was fixed in Thunderbird 147.0.1 and Thunderbird 140.7.1.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Mageia:9 | thunderbird | 0 | 140.7.1-1.mga9 |
| Mageia:9 | thunderbird-l10n | 0 | 140.7.1-1.mga9 |
| SUSE:Linux Enterprise Module for Package Hub 15 SP7 | MozillaThunderbird | 0 | 140.7.1-150200.8.254.1 |
| SUSE:Linux Enterprise Workstation Extension 15 SP7 | MozillaThunderbird | 0 | 140.7.1-150200.8.254.1 |
| openSUSE:Leap 15.6 | MozillaThunderbird | 0 | 140.7.1-150200.8.254.1 |
| openSUSE:Leap 16.0 | MozillaThunderbird | 0 | 140.8.1-bp160.1.1 |
| openSUSE:Tumbleweed | MozillaThunderbird | 0 | 140.7.1-1.1 |
Related vulnerabilities
- CVE-2026-0885 Use-after-free in the JavaScript: GC component. Also affects thunderbird
- CVE-2026-0890 Spoofing issue in the DOM: Copy & Paste and Drag & Drop component. Also affects thunderbird
- CVE-2026-0886 Incorrect boundary conditions in the Graphics component. Also affects thunderbird
- CVE-2026-0887 Clickjacking issue, information disclosure in the PDF Viewer component. Also affects thunderbird
- CVE-2026-0891 Memory safety bugs present in Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146 and… Also affects thunderbird
- CVE-2026-0877 Mitigation bypass in the DOM: Security component. Also affects thunderbird
- CVE-2026-0883 Information disclosure in the Networking component. Also affects thunderbird
- CVE-2026-0878 Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL… Also affects thunderbird