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CVE-2026-84458: Product identification pending

Severity

9.1 (CRITICAL)

Affected versions

Before 7.1.2

Fixed version

7.1.2.

Patch status

Patched

Published

2026-09-25T19:17:57.130

Modified

2026-09-25T19:17:57.130

Why it matters

This matters because the issue affects identity or token handling. Successful exploitation could allow unauthorized authentication, client manipulation, or access to protected services.

Recommended admin actions

• Prioritize validation immediately due to critical CVSS severity.
• Compare installed versions against the affected version range in the advisory.
• Review logs for suspicious activity related to the affected application or component.

Technical summary

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.

View the official NVD record for CVE-2026-84458

CVE data is sourced from NVD/CNA records and optional enrichment. Validate against the vendor advisory before taking production action.