CVE-2026-42392

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-28 · updated 2026-09-03
Weakness: CWE-200

Description

An attacker that has valid credentials can send an invalid IMAP URLFETCH command, which causes uninitialized memory to be included in the error response returned to the client. Process memory contents can be disclosed to the client, which may include sensitive data. Disable the IMAP URLAUTH functionality. Update to non-vulnerable version. No publicly available exploits are known.

Affected products

Open-Xchange GmbH OX Dovecot CE: from 2.3.0 before 2.4.5 — fixed in 2.4.5
Open-Xchange GmbH OX Dovecot Pro: from 2.3.0 before 3.1.6 — fixed in 3.1.6

How to fix

Upgrade to a fixed version: Open-Xchange GmbH OX Dovecot CE 2.4.5; Open-Xchange GmbH OX Dovecot Pro 3.1.6. Check the vendor advisory for mitigations.

References

https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json

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