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NVD Vulnerability Details :
CVE-2026-27857
Analyzed
More InfoOfficial Page
Source-security@open-xchange.com
View Known Exploited Vulnerability (KEV) details
Published At-27 Mar, 2026 | 09:16
Updated At-30 Apr, 2026 | 17:42

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.

CISA Catalog
Date AddedDue DateVulnerability NameRequired Action
N/A
Date Added: N/A
Due Date: N/A
Vulnerability Name: N/A
Required Action: N/A
Metrics
TypeVersionBase scoreBase severityVector
Secondary3.14.3MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Primary3.17.5HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Type: Secondary
Version: 3.1
Base score: 4.3
Base severity: MEDIUM
Vector:
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Type: Primary
Version: 3.1
Base score: 7.5
Base severity: HIGH
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CPE Matches

Dovecot
dovecot
>>dovecot>>Versions before 2.4.3(exclusive)
cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*
Open-Xchange AG
open-xchange
>>dovecot>>Versions before 2.3.22.1(exclusive)
cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*
Open-Xchange AG
open-xchange
>>dovecot>>Versions from 3.0.0(inclusive) to 3.0.5(exclusive)
cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*
Open-Xchange AG
open-xchange
>>dovecot>>Versions from 3.1.0(inclusive) to 3.1.4(exclusive)
cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*
Weaknesses
CWE IDTypeSource
CWE-400Secondarysecurity@open-xchange.com
CWE ID: CWE-400
Type: Secondary
Source: security@open-xchange.com
Evaluator Description

Evaluator Impact

Evaluator Solution

Vendor Statements

References
HyperlinkSourceResource
https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.jsonsecurity@open-xchange.com
Vendor Advisory
Hyperlink: https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json
Source: security@open-xchange.com
Resource:
Vendor Advisory
Change History
0Changes found

Details not found