Quick answers
- Is CVE-2026-118178 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-118178 being exploited in the wild.
- How severe is CVE-2026-118178?
- Informational severity, published 27 October 2026.
- Which products and versions are affected?
- Mozilla Thunderbird before 159 and before 153.6.
- Is there a fix for CVE-2026-118178?
- 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-2026-118178 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-118178?
- 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
The vulnerability exists in Thunderbird's handling of RSS feed redirection elements (itunes:new-feed-url or newLocation), which can be exploited to permanently change a stored subscription URL to a file: URL. Thunderbird then attempts to read from this location on every feed update without validating the URL scheme. An attacker with a malicious RSS feed or one able to modify feeds over HTTP can trigger local file reads (all platforms) or NTLM credential leaks on Windows when accessing remote network shares.
Affected products
- Mozilla Thunderbird before 159 and before 153.6
Timeline
- 2026-10-27: disclosed
- 2026-10-27: patched