Open-Xchange Dovecot Pro/Dovecot CE denial of service

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.8$0-$5k1.10-

Summaryinfo

A vulnerability classified as problematic was found in Open-Xchange Dovecot Pro and Dovecot CE. This affects an unknown function. The manipulation results in denial of service. This vulnerability is known as CVE-2026-42395. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Open-Xchange Dovecot Pro and Dovecot CE (version unknown). It has been classified as problematic. Affected is an unknown function. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. CVE summarizes:

A host listed as a trusted proxy can send forwarding information containing a NUL byte, which crashes the login process on the following login attempt. The login process is terminated, which can cause degradation or denial of service for logins. Deployments that do not configure trusted proxies are not affected. Restrict the list of trusted proxy networks to hosts that are fully under your control. Update to non-vulnerable version. No publicly available exploits are known.

The advisory is available at documentation.open-xchange.com. This vulnerability is traded as CVE-2026-42395 since 04/27/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-3076). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Open Source Dovecot

Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.8
VulDB Meta Temp Score: 4.8

VulDB Base Score: 5.3
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.3
CNA Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/27/2026 CVE reserved
08/28/2026 +123 days Advisory disclosed
08/28/2026 +0 days VulDB entry created
08/28/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: open-xchange.com

Advisory: documentation.open-xchange.com
Status: Not defined

CVE: CVE-2026-42395 (🔒)
GCVE (CVE): GCVE-0-2026-42395
GCVE (VulDB): GCVE-100-396690
CERT Bund: WID-SEC-2026-3076 - Dovecot: Mehrere Schwachstellen

Entryinfo

Created: 08/28/2026 13:58
Updated: 08/28/2026 19:37
Changes: 08/28/2026 13:58 (60), 08/28/2026 19:37 (7)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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