CVE-2026-118177

Full vulnerability record from the local CVENow database.

Description

When 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.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Deferred

Source identifier

[email protected]

Published

2026-10-27 19:17:29.370000

Last modified

2026-10-28 14:42:32.260000

View original CVE JSON

{
  "id": "CVE-2026-118177",
  "sourceIdentifier": "[email protected]",
  "published": "2026-10-27T19:17:29.370",
  "lastModified": "2026-10-28T14:42:32.260",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "When 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."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Mozilla",
          "product": "Thunderbird",
          "versions": [
            {
              "version": "153.6",
              "lessThanOrEqual": "153.*",
              "versionType": "rpm",
              "status": "unaffected"
            },
            {
              "version": "159",
              "lessThanOrEqual": "*",
              "versionType": "rpm",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2080924",
      "source": "[email protected]"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-121/",
      "source": "[email protected]"
    },
    {
      "url": "https://www.mozilla.org/security/advisories/mfsa2026-122/",
      "source": "[email protected]"
    }
  ]
}