CVE-2020-7046Network attack vector

Unauthenticated service exhaustion via truncated UTF-8 commands

Published Feb 12, 2020 · Updated Aug 4, 2024

Denial of service in Dovecot 2.3.9 allows remote attackers to exhaust submission-login and LMTP processes with truncated UTF-8 commands. The smtp_command_parse_parameters function repeats parsing when the UTF-8 decoder returns zero for an incomplete terminal character without advancing the input pointer. An unauthenticated submission-login connection is sufficient; each stuck process consumes 100% CPU and can exhaust available service processes.

CVSS severity7.5
High
EPSS probability51.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Dovecot 2.3.9 allows remote attackers to exhaust submission-login and LMTP processes with truncated UTF-8 commands. The smtp_command_parse_parameters function repeats parsing when the UTF-8 decoder returns zero for an incomplete terminal character without advancing the input pointer. An unauthenticated submission-login connection is sufficient; each stuck process consumes 100% CPU and can exhaust available service processes.

The record

CVE
CVE-2020-7046
Published
Feb 12, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-835, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 12, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5MITRECVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.8NVDAV:N/AC:L/Au:N/C:N/I:N/A:C
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Open-XchangeCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
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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