CVE-2026-27857 | BDVDB-2026-323367 Detail
Open-XchangeOX Dovecot Pro
Description#
Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Install fixed version, there is no other remediation. No publicly available exploits are known.
Impact#
Per CVSS v3.1: confidentiality impact none, integrity impact none, availability impact low. Attack vector: network.
Weaknesses#
References#
- https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json
- https://access.redhat.com/security/cve/CVE-2026-27857
- https://bugzilla.redhat.com/show_bug.cgi?id=2452179
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27857.json
- https://access.redhat.com/errata/RHSA-2026:26564
- https://access.redhat.com/errata/RHSA-2026:17602
- https://access.redhat.com/errata/RHSA-2026:13498
- https://access.redhat.com/errata/RHSA-2026:19149
- https://access.redhat.com/errata/RHSA-2026:13830
- https://access.redhat.com/errata/RHSA-2026:19455
- https://access.redhat.com/errata/RHSA-2026:19453
- https://access.redhat.com/errata/RHSA-2026:18053
- https://access.redhat.com/errata/RHSA-2026:17630
- https://access.redhat.com/errata/RHSA-2026:17628
- https://access.redhat.com/errata/RHSA-2026:17625
Exploit#
No public exploit known
History#
- Version 1Record published in the CVE List.
- Version 2Most recent update recorded in the CVE List.