CVE-2026-40016

Description

Attacker can upload a malicious Sieve script over ManageSieve service (or locally) to bypass configured CPU time limits for Sieve up to 130 times of the configured limit. Attacker can use this to degrade server performance and bypass configured CPU time limits for Sieve scripts. Install fixed version, or alternatively prevent direct access to Sieve scripts via ManageSieve or local access. No publicly available exploits are known.

PUBLISHED Reserved 2026-04-08 | Published 2026-05-12 | Updated 2026-05-12 | Assigner OX

Problem types

Uncontrolled Resource Consumption

Product status

References

documentation.open-xchange.com/...26/oxdc-adv-2026-0002.json vendor-advisory

cve.org (CVE-2026-40016)

nvd.nist.gov (CVE-2026-40016)

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