Calendar discovery accepted local file and remote network share locations

Summary

CVECVE-2026-118177
StatePUBLISHED
Assignermozilla
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-27 19:17:29 UTC
Updated2026-10-27 19:17:29 UTC
DescriptionWhen looking for calendars in a directory on a server, during account setup or when adding a new network calendar, Thunderbird accepted calendar locations pointing to other servers, local files or network shares. A malicious server, or a network attacker when the lookup used plain HTTP, could make Thunderbird subscribe to such a location. On Windows this could leak the user's NTLM credentials to an attacker-controlled host on every calendar refresh, and changes to the calendar could be written to the attacker's share or overwrite a local file. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mozilla Thunderbird unaffected 153.6 153.* rpm Not specified
CNA Mozilla Thunderbird unaffected 159 * rpm Not specified

References

ReferenceSourceLinkTags
www.mozilla.org/security/advisories/mfsa2026-122 [email protected] www.mozilla.org
bugzilla.mozilla.org/show_bug.cgi [email protected] bugzilla.mozilla.org
www.mozilla.org/security/advisories/mfsa2026-121 [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: Magnus Melin (en)

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