VulnerabilityAwaiting Analysis

CVE-2026-113866

Due to a bug, that unencrypted request included the credentials the user had entered, allowing a network attacker to obtain the user's password.

MEDIUM 5.9EPSS 0.36%

Does this matter?

Lower severity and a low EPSS score (0.36%). Track it; it rarely justifies an emergency change on its own.

Description

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.

CVSS 3.1: 5.9 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS: 0.36% probability · 30th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Weakness: CWE-523
Source: security@mozilla.org

EPSS trend

EPSS moved from 0.4% on 21 October 2026 to 0.4% on 27 October 2026.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.