CVE-2024-23184Network attack vector

Mail-service outage via quadratic address-header parsing

Published Sep 10, 2024 · Updated Nov 4, 2025

Resource exhaustion in OX Dovecot Pro 2.3.21 and earlier allows remote attackers to interrupt mail service via crafted messages. The lib-mail parser appends each address header to a linked list by walking the entire list, causing quadratic CPU growth as headers accumulate. An external sender who can deliver mail to a hosted recipient can consume minutes of CPU time and cause an outage without authenticating to Dovecot.

CVSS severity5.0
Medium
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in OX Dovecot Pro 2.3.21 and earlier allows remote attackers to interrupt mail service via crafted messages. The lib-mail parser appends each address header to a linked list by walking the entire list, causing quadratic CPU growth as headers accumulate. An external sender who can deliver mail to a hosted recipient can consume minutes of CPU time and cause an outage without authenticating to Dovecot.

The record

CVE
CVE-2024-23184
Published
Sep 10, 2024
Updated
Nov 4, 2025
Vendor
Open-Xchange GmbH
Product
OX Dovecot Pro
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 10, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record 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 <=2.3.21

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Open-Xchange GmbH · OX Dovecot Proversion=0 <=2.3.21

Published CVSS scores

5.0Open-Xchange GmbHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/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-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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