How severe is CVE-2020-5239?

CVE-2020-5239 has a CVSS 3.x base score of 8.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2020-5239 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-5239?

CVE-2020-5239 affects Mailu. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-5239?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-5239 published?

CVE-2020-5239 was published on 2020-02-13 and last updated on 2026-06-17.

CVE-2020-5239

CVE-2020-5239 is a high-severity vulnerability in Mailu with a CVSS 3.x base score of 8.7. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-863.

Key facts

Severity: High (CVSS 3.x base score 8.7)
CVSS v2: 6.5
EPSS exploit prediction: 1% (55th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-863
Affected product: Mailu
Published: 2020-02-13
Last modified: 2026-06-17

Description

In Mailu before version 1.7, an authenticated user can exploit a vulnerability in Mailu fetchmail script and gain full access to a Mailu instance. Mailu servers that have open registration or untrusted users are most impacted. The master and 1.7 branches are patched on our git repository. All Docker images published on docker.io/mailu for tags 1.5, 1.6, 1.7 and master are patched. For detailed instructions about patching and securing the server afterwards, see https://github.com/Mailu/Mailu/issues/1354

Frequently asked questions

What is CVE-2020-5239?: In Mailu before version 1.7, an authenticated user can exploit a vulnerability in Mailu fetchmail script and gain full access to a Mailu instance. Mailu servers that have open registration or untrusted users are most impacted. The master and 1.7 branches are patched on our git repository. All Docker images published on docker.io/mailu for tags 1.5, 1.6, 1.7 and master are patched. For detailed instructions about patching and securing the server afterwards, see https://github.com/Mailu/Mailu/issues/1354
How severe is CVE-2020-5239?: CVE-2020-5239 has a CVSS 3.x base score of 8.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2020-5239 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-5239?: CVE-2020-5239 affects Mailu. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-5239?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-5239 published?: CVE-2020-5239 was published on 2020-02-13 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mailu:mailu:*:*:*:*:*:*:*:*

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