Quick answers
- Is CVE-2026-118175 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-118175 being exploited in the wild.
- How severe is CVE-2026-118175?
- Informational severity, published 27 October 2026.
- Which products and versions are affected?
- Mozilla Thunderbird before 159, before 153.6.
- Is there a fix for CVE-2026-118175?
- Yes: fixed in Thunderbird 159, Thunderbird 153.6. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-118175 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-118175?
- Check whether you run Mozilla Thunderbird at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: Thunderbird 159, Thunderbird 153.6
Technical details
When a user replies to, forwards, or edits a crafted email message as a new message, Thunderbird can embed parts of a different message from the same folder into the composed message without displaying a blocked content warning. The vulnerability allows an attacker to craft a malicious email that, when replied to or forwarded by the recipient, leaks content from another message in the folder to the recipients of the reply.
Affected products
- Mozilla Thunderbird before 159, before 153.6
Timeline
- 2026-10-27: disclosed