CVE-2024-23184

dovecot: using a large number of address headers may trigger a denial of service

Published Sep 10, 2024 CVSS 3.1 · 5 Medium EPSS < 1% KEV · Not listed
Description
Having a large number of address headers (From, To, Cc, Bcc, etc.) becomes excessively CPU intensive. With 100k header lines CPU usage is already 12 seconds, and in a production environment we observed 500k header lines taking 18 minutes to parse. Since this can be triggered by external actors sending emails to a victim, this is a security issue. An external attacker can send specially crafted messages that consume target system resources and cause outage. One can implement restrictions on address headers on MTA component preceding Dovecot. No publicly available exploits are known.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-3860-1 dovecot security update
Debian DSA Debian DSA DSA-5752-1 dovecot security update
EUVD EUVD EUVD-2024-20703 Having a large number of address headers (From, To, Cc, Bcc, etc.) becomes excessively CPU intensive. With 100k header lines CPU usage is already 12 seconds, and in a production environment we observed 500k header lines taking 18 minutes to parse. Since this can be triggered by external actors sending emails to a victim, this is a security issue. An external attacker can send specially crafted messages that consume target system resources and cause outage. One can implement restrictions on address headers on MTA component preceding Dovecot. No publicly available exploits are known.
Ubuntu USN Ubuntu USN USN-6982-1 Dovecot vulnerabilities
Ubuntu USN Ubuntu USN USN-7013-1 Dovecot vulnerabilities
History
Type Values Removed Values Added
CPEs cpe:/a:redhat:enterprise_linux:8
Type Values Removed Values Added
First Time appeared Redhat enterprise Linux
CPEs cpe:/a:redhat:enterprise_linux:9
Vendors & Products Redhat enterprise Linux
Type Values Removed Values Added
Description A flaw was found in Dovecot. Processing a large number of address headers (From, To, Cc, Bcc, etc) can be excessively CPU intensive. This flaw allows a remote attacker to trigger a denial of service. Having a large number of address headers (From, To, Cc, Bcc, etc.) becomes excessively CPU intensive. With 100k header lines CPU usage is already 12 seconds, and in a production environment we observed 500k header lines taking 18 minutes to parse. Since this can be triggered by external actors sending emails to a victim, this is a security issue. An external attacker can send specially crafted messages that consume target system resources and cause outage. One can implement restrictions on address headers on MTA component preceding Dovecot. No publicly available exploits are known.
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV3_1

{'score': 5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N'}

Type Values Removed Values Added
First Time appeared Redhat
Redhat rhel Eus
CPEs cpe:/a:redhat:rhel_eus:9.2
Vendors & Products Redhat
Redhat rhel Eus
Type Values Removed Values Added
Description No description is available for this CVE. A flaw was found in Dovecot. Processing a large number of address headers (From, To, Cc, Bcc, etc) can be excessively CPU intensive. This flaw allows a remote attacker to trigger a denial of service.
Type Values Removed Values Added
Description No description is available for this CVE.
Title dovecot: using a large number of address headers may trigger a denial of service
Weaknesses CWE-770
References
Metrics threat_severity

None

cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Weaknesses

Sources

Status
PUBLISHED
Assigner
OX
Published
Updated
Nov 4, 2025, 4:11 PM
Reserved
Jan 12, 2024, 7:03 AM
Status
Deferred
Published
Sep 10, 2024, 3:15 PM
Modified
Jun 17, 2026, 7:12 AM
Severity
Moderate
Public date
Aug 15, 2024, 12:00 AM