CVE-2023-26430: Open-Xchange Appsuite Backend

Medium severity, CVSS 4.3. EPSS: 0.8% chance of exploitation in the next 30 days.

Attackers with access to user accounts can inject arbitrary control characters to SIEVE mail-filter rules. This could be abused to access SIEVE extension that are not allowed by App Suite or to inject rules which would break per-user filter processing, requiring manual cleanup of such rules. We have added sanitization to all mail-filter APIs to avoid forwardning control characters to subsystems. No publicly available exploits are known.

Affected products

• Open-Xchange Open-Xchange Appsuite Backend: version 7.10.6 only; version 8.10.0 only

Published 2023-08-02. Last modified 2026-06-17.