How severe is CVE-2019-20889?

CVE-2019-20889 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2019-20889 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-20889?

CVE-2019-20889 primarily affects Mattermost Mattermost Server. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-20889?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2019-20889 published?

CVE-2019-20889 was published on 2020-06-19 and last updated on 2026-06-17.

CVE-2019-20889

CVE-2019-20889 is a medium-severity vulnerability in Mattermost Mattermost Server with a CVSS 3.x base score of 5.3. 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-276.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-276
Affected product: Mattermost Mattermost Server
Published: 2020-06-19
Last modified: 2026-06-17

Description

An issue was discovered in Mattermost Server before 5.7, 5.6.3, 5.5.2, and 4.10.5. It mishandles permissions for user-access token creation.

Frequently asked questions

What is CVE-2019-20889?: An issue was discovered in Mattermost Server before 5.7, 5.6.3, 5.5.2, and 4.10.5. It mishandles permissions for user-access token creation.
How severe is CVE-2019-20889?: CVE-2019-20889 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2019-20889 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-20889?: CVE-2019-20889 primarily affects Mattermost Mattermost Server. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-20889?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-20889 published?: CVE-2019-20889 was published on 2020-06-19 and last updated on 2026-06-17.

References

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

Affected products (7)

cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
cpe:2.3:a:mattermost:mattermost_server:5.7.0:rc1:*:*:*:*:*:*
cpe:2.3:a:mattermost:mattermost_server:5.7.0:rc2:*:*:*:*:*:*
cpe:2.3:a:mattermost:mattermost_server:5.7.0:rc3:*:*:*:*:*:*
cpe:2.3:a:mattermost:mattermost_server:5.7.0:rc4:*:*:*:*:*:*
cpe:2.3:a:mattermost:mattermost_server:5.7.0:rc5:*:*:*:*:*:*
cpe:2.3:a:mattermost:mattermost_server:5.7.0:rc6:*:*:*:*:*:*

More vulnerabilities in Mattermost Mattermost Server

CVE-2025-12421 — Critical (CVSS 9.9): Mattermost versions 11.0.x <= 11.0.2, 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12 fail to to verify that…
CVE-2025-12419 — Critical (CVSS 9.9): Mattermost versions 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12, 11.0.x <= 11.0.3 fail to properly…
CVE-2025-4981 — Critical (CVSS 9.9): Mattermost versions 10.5.x <= 10.5.5, 9.11.x <= 9.11.15, 10.8.x <= 10.8.0, 10.7.x <= 10.7.2, 10.6.x <= 10.6.5 fail to…
CVE-2025-25279 — Critical (CVSS 9.9): Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate…
CVE-2025-20051 — Critical (CVSS 9.9): Mattermost versions 10.4.x <= 10.4.1, 9.11.x <= 9.11.7, 10.3.x <= 10.3.2, 10.2.x <= 10.2.2 fail to properly validate…
CVE-2017-18920 — Critical (CVSS 9.8): An issue was discovered in Mattermost Server before 3.6.2. The WebSocket feature does not follow the Same Origin Policy.

All CVEs affecting Mattermost Mattermost Server →

Other CWE-276 (Incorrect Default Permissions) vulnerabilities

CVE-2022-42150 — Critical (CVSS 10.0): TinyLab linux-lab v1.1-rc1 and cloud-labv0.8-rc2, v1.1-rc1 are vulnerable to insecure permissions. The default…
CVE-2020-29492 — Critical (CVSS 10.0): Dell Wyse ThinOS 8.6 and prior versions contain an insecure default configuration vulnerability. A remote…
CVE-2020-29491 — Critical (CVSS 10.0): Dell Wyse ThinOS 8.6 and prior versions contain an insecure default configuration vulnerability. A remote…
CVE-2025-40585 — Critical (CVSS 9.9): A vulnerability has been identified in Energy Services (All versions with G5DFR). Affected solutions using G5DFR…
CVE-2019-19896 — Critical (CVSS 9.9): In IXP EasyInstall 6.2.13723, there is Remote Code Execution via weak permissions on the Engine Service share. The…
CVE-2020-37129 — Critical (CVSS 9.8): Memu Play 7.1.3 contains an insecure folder permissions vulnerability that allows low-privileged users to modify the…

Browse all CWE-276 (Incorrect Default Permissions) vulnerabilities →