CVE-2018-21259

5.3 mediumEPSS 1.1%

Medium (5.3) in mattermost mattermost server. EPSS 1.1% chance of exploitation in the next 30 days.

An issue was discovered in Mattermost Server before 4.10.1, 4.9.4, and 4.8.2. It allows attackers to cause a denial of service (application hang) via a malformed link in a channel.

Severity

CVSS 3.1

5.3 medium

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

EPSS: 1.1% chance of exploitation in the next 30 days; higher than 65% of CVEs (scores of 2026-10-31)
CWE: CWE-20
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/

Check your stack JSON