Thunderbird <159/153.6 Email Composition Content Disclosure
CVE-2026-118175 Published on October 27, 2026
Content of other messages could be included when replying to a crafted message
When replying to, forwarding, or editing a crafted email message as new, Thunderbird could embed parts of a different message stored in the same folder into the message being composed, without showing a blocked content warning. If the user sent the message, the content of the other message was disclosed to the recipients. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
Vulnerability Analysis
CVE-2026-118175 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Weakness Type
What is an Information Disclosure Vulnerability?
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
CVE-2026-118175 has been classified to as an Information Disclosure vulnerability or weakness.
Products Associated with CVE-2026-118175
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Affected Versions
Mozilla Thunderbird:- Version 153.6, <= 153.* is unaffected.
- Version 159, <= * is unaffected.