---
cve: "CVE-2026-27856"
severity: "HIGH"
cvss: 7.4
epss: "39%"
vendor: "Open-Xchange GmbH"
kev: false
exploited: false
published: "2026-03-27 09:16:19"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-03T01:38:39+02:00"
---

# CVE-2026-27856

> 7.4 HIGH

## Beschreibung

Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An attacker can use this to determine the configured credentials. Figuring out the credential will lead into full access to the affected component. Limit access to the doveadm http service port, install fixed version. No publicly available exploits are known.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- c1b22ef978ca72999e254b2f3964b3d32d1a4979 (Commit)

## Referenzen

- <https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json>
- <https://access.redhat.com/errata/RHSA-2026:26564>
- <https://access.redhat.com/security/cve/CVE-2026-27856>
- <https://bugzilla.redhat.com/show_bug.cgi?id=2452171>
- <https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27856.json>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-27856) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_