CVE-2019-20866

5.3 mediumEPSS 0.9%

Medium (5.3) in mattermost mattermost server. EPSS 0.9% chance of exploitation in the next 30 days.

An issue was discovered in Mattermost Server before 5.12.0. Use of a Proxy HTTP header, rather than the source address in an IP packet header, for obtaining IP address information was mishandled.

Severity

CVSS 3.1

5.3 medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS: 0.9% chance of exploitation in the next 30 days; higher than 60% of CVEs (scores of 2026-10-31)
CWE: CWE-444
Published: 2020-06-19
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

mattermost:mattermost_server

References

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

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