CVE-2026-27860Network attack vector

LDAP structure disclosure via unescaped usernames

Published Mar 27, 2026 · Updated Mar 27, 2026

LDAP injection in Open-Xchange Dovecot Pro 2.4.0 and 3.1.0 allows remote attackers to probe LDAP structure via crafted usernames. The auth-ldap path inserts usernames into LDAP filters without escaping when auth_username_chars is configured as an empty string. Exposure requires LDAP authentication and the nondefault empty setting; injected filter syntax can bypass query restrictions and disclose directory structure.

CVSS severity3.7
Low
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

LDAP injection in Open-Xchange Dovecot Pro 2.4.0 and 3.1.0 allows remote attackers to probe LDAP structure via crafted usernames. The auth-ldap path inserts usernames into LDAP filters without escaping when auth_username_chars is configured as an empty string. Exposure requires LDAP authentication and the nondefault empty setting; injected filter syntax can bypass query restrictions and disclose directory structure.

The record

CVE
CVE-2026-27860
Published
Mar 27, 2026
Updated
Mar 27, 2026
Vendor
Open-Xchange GmbH
Product
Dovecot Pro
Classifications
CWE-90, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.4.0
  2. Affected versionversion=0 <=3.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Open-Xchange GmbH · Dovecot Proversion=0 <=2.4.0; version=0 <=3.1.0

Published CVSS scores

3.7Open-XchangeCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-90Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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