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.
Metrics
Affected Vendors & Products
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Advisories
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Fixes
Solution
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Workaround
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References
History
Tue, 10 Nov 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | 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. |
| References |
|
Tue, 10 Nov 2026 19:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | OAuth2 access token could be sent over an unencrypted connection with Exchange accounts | |
| References |
|
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MITRE
Status: PUBLISHED
Assigner: mozilla
Published:
Updated: 2026-11-10T20:24:08.458Z
Reserved: 2026-11-10T18:59:57.660Z
Link: CVE-2026-126136
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2026-11-10T19:21:14.313
Modified: 2026-11-10T21:19:27.973
Link: CVE-2026-126136
Redhat
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OpenCVE Enrichment
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Weaknesses
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