CVE-2026-27857
- State
- Published
- Severity
- 4.3 Medium
- Published
- Mar 27, 2026
- Updated
- Jul 15, 2026
- Reserved
- Feb 24, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 4.3 Medium | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L | OX |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat-SADP |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
OX Dovecot ProOpen-Xchange GmbH |
|
References
- https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.jsonvendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-27857vdb-entry
- RHBZ#2452179issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27857.json
- https://access.redhat.com/errata/RHSA-2026:26564vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:17602vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:13498vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:19149vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:13830vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:19455vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:19453vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:18053vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:17630vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:17628vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:17625vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:17626vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:13857vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:19364vendor-advisory
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.