An issue was discovered in Mattermost Server before 5.19.0.

published 2020-06-19 6y ago modified 2026-06-17 4mo ago also BIT-mattermost-2020-14458 , EUVD-2020-6595

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.1%; EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits: 0; none known

An issue was discovered in Mattermost Server before 5.19.0. Attackers can discover private channels via the "get channel by name" API, aka MMSA-2020-0004.

Patch / fix

fixed in 2

bitnami mattermost 5.19.0
mattermost mattermost_server 5.19.0

Is CVE-2020-14458 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Exploit prediction

1.14% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:P/I:N/A:N
OSV	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
bitnami	mattermost	<5.19.0	5.19.0

References

mattermost.com /security-updates/
vendor-advisory, web
nvd.nist.gov /vuln/detail/CVE-2020-14458
web

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.