CVE-2026-126136 (GCVE-0-2026-126136)

Vulnerability from cvelistv5 – Published: 2026-11-10 18:59 – Updated: 2026-11-10 20:24
VLAI
Title
OAuth2 access token could be sent over an unencrypted connection with Exchange accounts
Summary
For Exchange accounts using EWS or Microsoft Graph with OAuth2 authentication, Thunderbird sent the OAuth2 access token to the server even when the configured server URL used unencrypted HTTP. An attacker able to observe network traffic could obtain the token and use it to access the user's mailbox until the token expired. An attacker positioned on the network during account setup could cause such a URL to be configured. This vulnerability was fixed in Thunderbird 160 and Thunderbird 153.7.
Severity
No CVSS data available.
Assigner
mozilla CNA
References
Impacted products
Vendor Product Version
Mozilla Thunderbird Unaffected: 153.7 , ≤ 153.* (rpm)
Unaffected: 160 , ≤ * (rpm)
Create a notification for this product.
Credits
Álvaro Chico Martínez
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "Thunderbird",
          "vendor": "Mozilla",
          "versions": [
            {
              "lessThanOrEqual": "153.*",
              "status": "unaffected",
              "version": "153.7",
              "versionType": "rpm"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "160",
              "versionType": "rpm"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "\u00c1lvaro Chico Mart\u00ednez"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "For Exchange accounts using EWS or Microsoft Graph with OAuth2 authentication, Thunderbird sent the OAuth2 access token to the server even when the configured server URL used unencrypted HTTP. An attacker able to observe network traffic could obtain the token and use it to access the user\u0027s mailbox until the token expired. An attacker positioned on the network during account setup could cause such a URL to be configured. This vulnerability was fixed in Thunderbird 160 and Thunderbird 153.7."
            }
          ],
          "value": "For Exchange accounts using EWS or Microsoft Graph with OAuth2 authentication, Thunderbird sent the OAuth2 access token to the server even when the configured server URL used unencrypted HTTP. An attacker able to observe network traffic could obtain the token and use it to access the user\u0027s mailbox until the token expired. An attacker positioned on the network during account setup could cause such a URL to be configured. This vulnerability was fixed in Thunderbird 160 and Thunderbird 153.7."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-10T20:24:08.458Z",
        "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
        "shortName": "mozilla"
      },
      "references": [
        {
          "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=2085865"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-128/"
        },
        {
          "url": "https://www.mozilla.org/security/advisories/mfsa2026-129/"
        }
      ],
      "title": "OAuth2 access token could be sent over an unencrypted connection with Exchange accounts"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
    "assignerShortName": "mozilla",
    "cveId": "CVE-2026-126136",
    "datePublished": "2026-11-10T18:59:58.290Z",
    "dateReserved": "2026-11-10T18:59:57.660Z",
    "dateUpdated": "2026-11-10T20:24:08.458Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}



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