What is CVE-2019-20870?

CVE-2019-20870 is a medium-severity vulnerability in Mattermost Server, classified under Improper Input Validation. CVSS score: 4.3/10. Published 2020-06-19.

How severe is CVE-2019-20870?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Improper input validation in Mattermost Server

CVE-2019-20870

An issue was discovered in Mattermost Server before 5.10.0. An attacker can bypass the intended appearance of the Edited flag after changing a post's file ID.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2020-06-19 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (51.4th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Mattermost Server

Weakness classification (CWE)

CWE-20 — Improper Input Validation

References

mattermost.com/security-updates/ (Vendor Advisory)

Frequently asked questions

What is CVE-2019-20870?: CVE-2019-20870 is a medium-severity vulnerability in Mattermost Server, classified under Improper Input Validation. CVSS score: 4.3/10. Published 2020-06-19.
How severe is CVE-2019-20870?: Medium severity. CVSS v3 base score is 4.3 out of 10.