Quick answers
- Is CVE-2026-40019 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-40019 being exploited in the wild.
- How severe is CVE-2026-40019?
- Medium severity, with a CVSS score of 5.9, published 28 August 2026.
- Which products and versions are affected?
- Open-Xchange Dovecot Pro 2.3.0 to 2.3.22.1, 3.0.0 to 3.0.6, 3.1.0 to 3.1.5.
- Is there a fix for CVE-2026-40019?
- A patch was published on 2026-08-28: Patches available in versions 2.3.22.2, 3.0.7, and 3.1.6 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-40019 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-40019?
- 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
The vulnerability is a denial-of-service condition in the ManageSieve login process caused by improper handling of truncated quoted arguments. An unauthenticated, network-reachable attacker can trigger an infinite loop in the string parsing logic by sending a malformed quoted string parameter during authentication. No authentication is required to exploit this issue. The attack causes the affected ManageSieve process to consume CPU until manually killed, and multiple connections can exhaust server resources entirely. Patches are available in versions 2.3.22.2, 3.0.7, and 3.1.6 or later.
Affected products
- Open-Xchange Dovecot Pro 2.3.0 to 2.3.22.1, 3.0.0 to 3.0.6, 3.1.0 to 3.1.5
Timeline
- 2026-08-28: disclosed
- 2026-08-28: patched: Patches available in versions 2.3.22.2, 3.0.7, and 3.1.6