CVE-2026-40019An unauthenticated attacker can send a truncated quoted argument to the ManageSieve login process, which makes it spin in an infinite loop consuming CPU.
Updated under an hour ago ()
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It affects Open-Xchange GmbH OX Dovecot CE. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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An unauthenticated attacker can send a truncated quoted argument to the ManageSieve login process, which makes it spin in an infinite loop consuming CPU. This can cause degradation or denial of service for Sieve script management, and repeated connections can consume all available CPU on the server. Monitor system for abnormal CPU usage and kill the offending process. Restrict network access to the ManageSieve service to trusted clients. Update to non-vulnerable version. No publicly available exploits are known.
- CVSS
- 5.9 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-400
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- OX
- NVD analysis
- Deferred
- Record last updated
- Aug 28, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Open-Xchange GmbH OX Dovecot CE open_xchange:ox_dovecot_ce (from the name) | from 2.4.3 before 2.4.5 | CNA record |
References
- https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.jsonvendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.