CVE-2026-332634.3MediumCWE-403

CVE-2026-33263: Open-Xchange GmbH OX Dovecot Pro vulnerability

Open-Xchange GmbH · OX Dovecot Pro

Vendor fix available · Affected: Open-Xchange GmbH OX Dovecot Pro · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.6%probability of exploitation in the next 30 days

46th percentile

050100

Higher than 46% of scored CVEs

4.3MediumCVSS 3.1

LowMediumHighCrit.

DescriptionCVE.org

When mail_max_userip_connections is set (default 10) and reached, submission-login can crash with epoll() panic caused by file descriptor handling issues. If running in high-security mode (default for community releases), only the new submission connection gets terminated. If running in high-performance mode (default for Pro releases), all connections handled by the submission-login process will be terminated. The crashes can cause failure for user to send a message, or it can cause duplicate messages to be sent. If TLS is not used (in the backend server processing the submission), duplicate deliveries cannot happen, because the crash can only happen at AUTH stage. Limit the number of connections handled by single submission-login process. This has a performance impact though. Update to non-vulnerable version. No publicly available exploits are known.

Affected products2

From the CVE record. A product or version that is not listed is unknown, not unaffected.

Open-Xchange GmbH · OX Dovecot Profrom 2.3.0 before 2.3.22.2; from 3.0.0 before 3.0.7; from 3.1.0 before 3.1.6
Open-Xchange GmbH · OX Dovecot CEfrom 2.3.0 before 2.4.5

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Exposure of File Descriptor to Unintended Control Sphere · Denial of Service
Vendor: Open-Xchange GmbH
Published: August 2026
Band: Unlikely (under 1%), August 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-33263 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.