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CVE-2026-0818
CSS-based exfiltration of the content from partially encrypted emails when allowing remote content
Description

CSS-based exfiltration of the content from partially encrypted emails when allowing remote content. This vulnerability affects Thunderbird < 147.0.1 and Thunderbird < 140.7.1.

INFO

Published Date :

Jan. 28, 2026, 8:16 a.m.

Last Modified :

Jan. 28, 2026, 8:16 a.m.

Remotely Exploit :

No

Source :

[email protected]
Affected Products

The following products are affected by CVE-2026-0818 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Mozilla thunderbird
: Total Affected Vendor : 1 | Products : 1
Solution
Update Thunderbird to a version that addresses CSS-based exfiltration risks from remote content.
  • Update Thunderbird to version 147.0.1 or later.
  • Update Thunderbird to version 140.7.1 or later.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-0818.

URL Resource
https://bugzilla.mozilla.org/show_bug.cgi?id=1881530
https://www.mozilla.org/security/advisories/mfsa2026-07/
https://www.mozilla.org/security/advisories/mfsa2026-08/
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-0818 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-0818 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-0818 vulnerability anywhere in the article.

  • security.nl
Thunderbird dicht lek dat aanvaller inhoud versleutelde e-mail laat stelen

De makers van e-mailclient Thunderbird hebben een beveiligingsupdate uitgebracht wegens een kwetsbaarheid waardoor een aanvaller de inhoud van versleutelde e-mail kan stelen. De Duitse overheid stelt ... Read more

Published Date: Jan 28, 2026 (1 hour, 37 minutes ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-0818 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Jan. 28, 2026

    Action Type Old Value New Value
    Added Description CSS-based exfiltration of the content from partially encrypted emails when allowing remote content. This vulnerability affects Thunderbird < 147.0.1 and Thunderbird < 140.7.1.
    Added Reference https://bugzilla.mozilla.org/show_bug.cgi?id=1881530
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-07/
    Added Reference https://www.mozilla.org/security/advisories/mfsa2026-08/
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
No CVSS metrics available for this vulnerability.