---
cve: "CVE-2026-84465"
severity: "HIGH"
cvss: 7.1
epss: ""
vendor: "Zammad"
kev: false
exploited: false
published: "2026-09-25 19:17:58"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-27T11:32:57+02:00"
---

# CVE-2026-84465

> 7.1 HIGH · 🧪 PoC

## Beschreibung

Zammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, when Zammad checks the digital signature on an incoming S/MIME-signed email, it does not verify that the signing certificate is genuinely trusted, it only checks whether a certificate with a matching name is already stored in the system. An attacker can create their own certificate using the name of a real, previously trusted sender and use it to send a forged email. Zammad will display that email with the same "validly signed" indicator as a genuine message from the real sender, even though the attacker never had access to that sender's actual certificate or private key. This issue is fixed in version 7.1.2.

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |

## Patch verfügbar (OSV)

- 9a07d0b8214ac4e8e10c23fce71d613bd0625524 (Commit)

## Referenzen

- <https://github.com/zammad/zammad/security/advisories/GHSA-m9ff-hjr3-93h4>
- <https://github.com/zammad/zammad/commit/9a07d0b8214ac4e8e10c23fce71d613bd0625524>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-84465) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_