CVE-2026-84458

Published: Set 25, 2026 Last Modified: Set 25, 2026
ExploitDB:
Other exploit source:
Google Dorks:
CRITICAL 9,1
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: none
Confidentiality: N/A
Integrity: N/A
Availability: N/A

Description

AI Translation Available

Zammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, when the 'Automatic account link on initial logon' setting is enabled, Zammad binds an incoming third-party (SSO) identity to an existing local account by matching the email address the identity provider reports, without verifying that the provider actually confirmed ownership of that email. An attacker who controls any identity at a configured provider, including, by default, any Azure AD tenant via Zammad's multi-tenant Microsoft 365 /common app registration, can set that identity's email to a victim's address, authenticate, and be logged in as the victim. This bypasses the victim's local password entirely and affects any existing account, including agents and administrators. Zammad will honor the xms_edov ID token claim when email verification is required in the Microsoft 365 setting, treating a missing claim as unverified. This issue is fixed in version 7.1.2.

287

Improper Authentication

Draft
Abstraction: Class Structure: Simple
Common Consequences
Security Scopes Affected:
Integrity Confidentiality Availability Access Control
Potential Impacts:
Read Application Data Gain Privileges Or Assume Identity Execute Unauthorized Code Or Commands
Applicable Platforms
Technologies: Not Technology-Specific, Web Based, ICS/OT
Likelihood of Exploit: High
View CWE Details
https://github.com/zammad/zammad/commit/0dba387df8e2b469569…
https://github.com/zammad/zammad/commit/0dba387df8e2b46956907975034cd44e4d021b1c
https://github.com/zammad/zammad/security/advisories/GHSA-8…
https://github.com/zammad/zammad/security/advisories/GHSA-86cc-3ggh-mf2m