CVE-2026-27852
High
Description
An attacker that can send mail to a user can craft a message whose headers contain a very large number of email addresses or MIME parameters, which causes excessive memory usage when the message is later parsed. The message is still delivered, but reading it over IMAP can exhaust the memory limit of the process and terminate it, causing denial of service for the affected user. Update to non-vulnerable version. No publicly available exploits are known.
SeverityHigh
CVSS7.5
Exploit probability—
ProductOX Dovecot Pro
PublishedAug 28, 2026
First seenAug 28, 2026
Weakness typeCWE-400Uncontrolled resource consumption
How to fix
Update
- Open-Xchange GmbH OX Dovecot Pro2.3.22.2, 3.0.7, 3.1.6 or later
- Open-Xchange GmbH OX Dovecot CE2.4.5 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Open-Xchange GmbH OX Dovecot Pro | 2.3.0 ≤ v < 2.3.22.2, 3.0.0 ≤ v < 3.0.7, 3.1.0 ≤ v < 3.1.6 | 2.3.22.2, 3.0.7, 3.1.6 |
| Open-Xchange GmbH OX Dovecot CE | 2.3.0 ≤ v < 2.4.5 | 2.4.5 |
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