CVE-2026-113866 (GCVE-0-2026-113866)

Vulnerability from cvelistv5 – Published: 2026-10-20 19:14 – Updated: 2026-10-20 19:46
VLAI
Title
Account password sent unencrypted during Exchange account setup
Summary
When setting up an account, Thunderbird's Exchange AutoDiscover lookup also queried the domain's AutoDiscover service over plain HTTP. Due to a bug, that unencrypted request included the credentials the user had entered, allowing a network attacker to obtain the user's password. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.
Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-20 19:35 UTC
CWE
  • CWE-523 - Unprotected Transport of Credentials
Assigner
mozilla CNA under the mitre root
CNA scorecard E 38/100 over 512 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Mozilla Thunderbird Unaffected: 153.5.1 , ≤ 153.* (rpm)
Unaffected: 158.0.1 , ≤ * (rpm)
guessed Create a notification for this product.
Credits
Magnus Melin
Show details on NVD website
To clipboard 

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