Calendar server credentials could be sent to an HTTP proxy
Summary
| CVE | CVE-2026-126133 |
|---|---|
| State | PUBLISHED |
| Assigner | mozilla |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-11-10 19:21:13 UTC |
| Updated | 2026-11-10 21:19:27 UTC |
| Description | 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. |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Mozilla | Thunderbird | unaffected 153.7 153.* rpm | Not specified |
| CNA | Mozilla | Thunderbird | unaffected 160 * rpm | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.mozilla.org/show_bug.cgi | [email protected] | bugzilla.mozilla.org | |
| www.mozilla.org/security/advisories/mfsa2026-128 | [email protected] | www.mozilla.org | |
| www.mozilla.org/security/advisories/mfsa2026-129 | [email protected] | www.mozilla.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Christopher Bohn (Protectstar Inc.) (en)
There are currently no legacy QID mappings associated with this CVE.