CVE Tools

CVE-2026-27857

Published: Mar 27, 2026Updated: Apr 30, 2026 Sources: CVE List NVDCWE-400
4.3CVSSMEDIUM

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.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:NI:NA:L
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:LAvailability
Low

Weaknesses

Affected Products

dovecotoss-projectCommunicationsaka dovecot, pigeonhole
open-xchangecommercialDECommunicationsaka open-xchange gmbh, ox
open-xchange gmbhcommercialDEEnterprise Softwareaka open-xchange

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

Timeline

Published
Mar 27, 2026
Last Updated
Apr 30, 2026

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