CVE-2026-126133 mozilla thunderbird
mozilla thunderbird: no CVSS score yet. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
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When a CalDAV or ICS calendar was accessed through an HTTP proxy that requested authentication, Thunderbird could answer the proxy with the calendar server's username and password. This affected both setting up a new calendar and syncing existing calendars, where a saved password could be sent without any user interaction. A malicious or compromised proxy could use this to obtain the calendar credentials, even for calendars served over HTTPS. This vulnerability was fixed in Thunderbird 160 and Thunderbird 153.7.
- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 11th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- Published
- Modified
- Assigned by
- mozilla (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
Versions
From the CNA's record in the CVE List.
Fixed in
| Product | Release line | Fixed in |
|---|---|---|
| Mozilla Thunderbird | 153 | 153.7 |
| Mozilla Thunderbird | later releases | 160 |
Fix and patched versions
- Mozilla Thunderbird: fixed in 153.7
- Mozilla Thunderbird: fixed in 160
- Debian: fixed package versions per release
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12 | thunderbird | 1:153.7.0esr-1~deb12u1 | DEBIAN-CVE-2026-126133 |
| Debian | 13 | thunderbird | 1:153.7.0esr-1~deb13u1 | DEBIAN-CVE-2026-126133 |
| Debian | 14 | thunderbird | no fix listed | DEBIAN-CVE-2026-126133 |
| Ubuntu | 22.04:LTS, 24.04:LTS, 26.04:LTS and 1 more | thunderbird | no fix listed | UBUNTU-CVE-2026-126133 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.