Quick answers
- Is CVE-2026-52687 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-52687 being exploited in the wild.
- How severe is CVE-2026-52687?
- Medium severity, with a CVSS score of 6.5, published 28 August 2026.
- Which products and versions are affected?
- Open-Xchange Dovecot Pro 2.3.0 to <2.3.22.2, 3.0.0 to <3.0.7, 3.1.0 to <3.1.6.
- Is there a fix for CVE-2026-52687?
- A patch was published on 2026-08-28. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-52687 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-52687?
- Check whether you run 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 flaw in Dovecot's IMAP compression handling. An attacker with valid email credentials can specify a compression algorithm for an IMAP connection whose decompression state consumes substantial memory. By opening several such connections in parallel, the process-level memory limit is rapidly exhausted, causing the imap-login process to terminate and resulting in denial of service for all connections handled by that process. The attack requires valid authentication credentials and is triggered during normal IMAP session negotiation. Patches are available in versions 2.3.22.2, 3.0.7, and 3.1.6 or later; workarounds include disabling IMAP compression or limiting connections per imap-login process.
Affected products
- Open-Xchange Dovecot Pro 2.3.0 to <2.3.22.2, 3.0.0 to <3.0.7, 3.1.0 to <3.1.6
Timeline
- 2026-08-28: disclosed
- 2026-08-28: patched