How severe is CVE-2019-20853?

CVE-2019-20853 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-20853 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-20853?

CVE-2019-20853 affects Mattermost Mattermost Packages. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2019-20853?

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

When was CVE-2019-20853 published?

CVE-2019-20853 was published on 2020-06-19 and last updated on 2026-06-17.

CVE-2019-20853

CVE-2019-20853 is a critical-severity vulnerability in Mattermost Mattermost Packages with a CVSS 3.x base score of 9.8. 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-668.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (81st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-668
Affected product: Mattermost Mattermost Packages
Published: 2020-06-19
Last modified: 2026-06-17

Description

An issue was discovered in Mattermost Packages before 5.16.3. A Droplet could allow Internet access to a service that has a remote code execution problem.

Frequently asked questions

What is CVE-2019-20853?: An issue was discovered in Mattermost Packages before 5.16.3. A Droplet could allow Internet access to a service that has a remote code execution problem.
How severe is CVE-2019-20853?: CVE-2019-20853 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-20853 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (81st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-20853?: CVE-2019-20853 affects Mattermost Mattermost Packages. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2019-20853?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2019-20853 published?: CVE-2019-20853 was published on 2020-06-19 and last updated on 2026-06-17.

References

https://mattermost.com/security-updates/

Affected products (1)

cpe:2.3:a:mattermost:mattermost_packages:*:*:*:*:*:*:*:*

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