CVE-2026-118180 (GCVE-0-2026-118180)
Vulnerability from cvelistv5
Published
2026-10-27 18:16
Modified
2026-10-27 18:27
Severity ?
Summary
When logging in to a Matrix account, Thunderbird used the homeserver address provided in the server's login response without validating it. A malicious or compromised homeserver could provide a file: URL, causing Thunderbird to send all further Matrix requests of that session to local files or, on Windows, to an attacker-controlled network share, which could leak the user's NTLM credentials. The NTLM credential leak only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6.
References
Impacted products
Vendor Product Version
Mozilla Thunderbird Unaffected: 153.6
Unaffected: 159
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "Thunderbird",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThanOrEqual": "153.*",
              "status": "unaffected",
              "version": "153.6",
              "versionType": "rpm"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "159",
              "versionType": "rpm"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Magnus Melin"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "When logging in to a Matrix account, Thunderbird used the homeserver address provided in the server\u0027s login response without validating it. A malicious or compromised homeserver could provide a file: URL, causing Thunderbird to send all further Matrix requests of that session to local files or, on Windows, to an attacker-controlled network share, which could leak the user\u0027s NTLM credentials.\u003cbr /\u003eThe NTLM credential leak only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6."
            }
          ],
          "value": "When logging in to a Matrix account, Thunderbird used the homeserver address provided in the server\u0027s login response without validating it. A malicious or compromised homeserver could provide a file: URL, causing Thunderbird to send all further Matrix requests of that session to local files or, on Windows, to an attacker-controlled network share, which could leak the user\u0027s NTLM credentials.\nThe NTLM credential leak only affects Thunderbird on Windows. Other operating systems are unaffected. This vulnerability was fixed in Thunderbird 159 and Thunderbird 153.6."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-27T18:27:53.280Z",
        "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
        "shortName": "mozilla"
      },
      "references": [
        {
          "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2080939"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-121/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-122/"
        }
      ],
      "title": "Matrix homeserver could redirect the chat session to a local file or network share"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
    "assignerShortName": "mozilla",
    "cveId": "CVE-2026-118180",
    "datePublished": "2026-10-27T18:16:33.495Z",
    "dateReserved": "2026-10-27T18:16:33.089Z",
    "dateUpdated": "2026-10-27T18:27:53.280Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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