Quick answers
- Is CVE-2026-42007 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-42007 being exploited in the wild.
- How severe is CVE-2026-42007?
- Critical severity, with a CVSS score of 9.1, 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-2026-42007?
- 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-2026-42007 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-42007?
- 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 use-after-free flaw in OX Dovecot's mail editing code triggered via the Sieve editheader extension. An authenticated attacker with valid credentials can craft a specially formed Sieve filter script to access memory after it has been freed, causing memory corruption and information disclosure. The vulnerability affects mail delivery operations and may allow arbitrary code execution in the context of the mail delivery process. No publicly available exploits are currently known. Patches are available: update to OX Dovecot Pro 2.3.22.2, 3.0.7, or 3.1.6 and later, or disable the Sieve editheader extension as a workaround.
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: Public disclosure of CVE-2026-42007
- 2026-08-26: advisory: Initial security advisory OXDC-ADV-2026-0003