🛡️ CVE-2026-27857
🟡 CVSS 4.3 — Medium ✅ No Known Exploit CWE-400 NVD
4.3
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

Details

Severity MEDIUM
CVSS Score 4.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CWE CWE-400
Public Exploit ✅ No
Source NVD
Published 2026-03-27
Updated 2026-06-02
Modified 2026-04-30
Fix URL N/A

Affected Packages

Software From version Fixed in
dovecot 3.1.0 3.1.4

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