CVE-2026-113866

Account password sent unencrypted during Exchange account setup

MEDIUM
5.9
CVSS Score
Published: October 20, 2026 at 07:14 PM UTC
Updated: October 22, 2026 at 05:36 PM UTC
Products not identified yet

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Severity
MEDIUM5.9
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

We have no canonical product record for this CVE. The source names may not have matched any product.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-523

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