CVE-2025-59028Network attack vector

Unauthenticated login disruption via invalid SASL base64

Published Mar 27, 2026 · Updated Mar 27, 2026

Improper input validation in OX Dovecot Pro core 2.4.0 and earlier or 3.1.0 and earlier allows remote attackers to interrupt concurrent logins. The login process disconnects from the authentication server after receiving invalid base64 SASL data, terminating every active authentication session attached to that process. No credentials or user interaction are required; the service interruption is limited to concurrent login attempts handled by the affected process.

CVSS severity7.5
High
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in OX Dovecot Pro core 2.4.0 and earlier or 3.1.0 and earlier allows remote attackers to interrupt concurrent logins. The login process disconnects from the authentication server after receiving invalid base64 SASL data, terminating every active authentication session attached to that process. No credentials or user interaction are required; the service interruption is limited to concurrent login attempts handled by the affected process.

The record

CVE
CVE-2025-59028
Published
Mar 27, 2026
Updated
Mar 27, 2026
Vendor
Open-Xchange GmbH
Product
Dovecot Pro
Classifications
CWE-20, T1499
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

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.3Open-XchangeCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

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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-20Improper Input Validation
T1499Endpoint Denial of Service

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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