CVE-2026-84458
Zammad: Account takeover via unverified email matching during SSO auto-link
No known exploitation. EPSS puts it in the 27th percentile. No fix published yet.
What to do
No fixed build or workaround is published yet. Limit exposure and watch for a patch.
- ZammadAffected: < 7.1.2Upgrade to: not statedStated by: CVE record
Versions as the sources state them. Full version matrix after sign-in
What it is
From the CVE record
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.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.4% chance of exploitation activity in the next 30 days, which ranks it in the 27th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
5 events over 3 days, from the signal feeds we watch.
- Record updated
- Publishedweakness classified, att&ck mapped, record updated
Affected products
Technical detail
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
Sources
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