Is CVE-2026-42006 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-42006 being exploited in the wild.

How severe is CVE-2026-42006?

Medium severity, with a CVSS score of 4.3, published 12 May 2026.

Which products and versions are affected?

Open-Xchange Dovecot CE 2.4.0, 2.4.3; Open-Xchange Dovecot Pro 2.3.0, 3.0.5, 3.1.0, 3.1.4.

Is there a fix for CVE-2026-42006?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-42006 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-42006?

Check whether you run Dovecot, Open-Xchange Dovecot CE or Open-Xchange Dovecot Pro at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-42006: Open-Xchange Dovecot uncontrolled memory consumption in IMAP

CVE-2026-42006 · Severity: medium · CVSS 4.3 · Published 2026-05-12

Open-Xchange Dovecot is a widely used email server. A vulnerability in its IMAP handling allows an attacker to send specially crafted commands that consume excessive server memory. This can lead to a denial-of-service condition where the email service becomes slow or unavailable for other users.

Technologies: Dovecot, Open-Xchange Dovecot CE, Open-Xchange Dovecot Pro. Vendors: Dovecot, Open-Xchange.

Quick answers

Is CVE-2026-42006 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-42006 being exploited in the wild.
How severe is CVE-2026-42006?: Medium severity, with a CVSS score of 4.3, published 12 May 2026.
Which products and versions are affected?: Open-Xchange Dovecot CE 2.4.0, 2.4.3; Open-Xchange Dovecot Pro 2.3.0, 3.0.5, 3.1.0, 3.1.4.
Is there a fix for CVE-2026-42006?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-42006 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-42006?: Check whether you run Dovecot, Open-Xchange Dovecot CE or Open-Xchange Dovecot Pro at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

This vulnerability is a resource exhaustion issue (CWE-400) in the IMAP component of Dovecot. It stems from an incomplete fix for CVE-2026-27857; while closing braces were previously restricted, an attacker can still use excessive open braces to bypass memory allocation limits. A remote attacker with basic user privileges can send these crafted IMAP commands to consume memory up to the configured process limit, potentially causing a denial of service. The issue is resolved in Dovecot Pro 3.1.5 and Dovecot CE 2.4.4. As a workaround, administrators can configure a low 'vsz_limit' for the IMAP process.

Affected products

Open-Xchange Dovecot Pro 2.3.0, 3.0.5, 3.1.0, 3.1.4
Open-Xchange Dovecot CE 2.4.0, 2.4.3

Timeline

2026-05-12: advisory: Initial public release of the advisory
2026-05-12: disclosed: NVD publication date

References

https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json

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