CVE-2020-5239Network attack vector

Authenticated full-instance compromise

Published Feb 13, 2020 · Updated Aug 4, 2024

Incorrect authorization in Mailu before 1.7 allows remote authenticated users to gain full instance access through the optional fetchmail service. The upstream advisory identifies the fetchmail script as the affected locus but does not disclose the flawed operation or attacker-controlled field. The flaw is reachable only when fetchmail is deployed, and open registration or untrusted accounts increase exposure.

CVSS severity8.7
High
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Mailu before 1.7 allows remote authenticated users to gain full instance access through the optional fetchmail service. The upstream advisory identifies the fetchmail script as the affected locus but does not disclose the flawed operation or attacker-controlled field. The flaw is reachable only when fetchmail is deployed, and open registration or untrusted accounts increase exposure.

The record

CVE
CVE-2020-5239
Published
Feb 13, 2020
Updated
Aug 4, 2024
Vendor
Mailu
Product
Mailu
Classifications
CWE-863, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 13, 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?

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

  1. Affected versionversion=< 1.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mailu · Mailuversion=< 1.7

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
8.7GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1068Exploitation for Privilege Escalation

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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