CVE-2021-37863

5.7 mediumEPSS 0.9%

Medium (5.7) in mattermost mattermost server. EPSS 0.9% chance of exploitation in the next 30 days.

Mattermost 6.0 and earlier fails to sufficiently validate parameters during post creation, which allows authenticated attackers to cause a client-side crash of the web application via a maliciously crafted post.

Severity

CVSS 3.1

5.7 medium

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

EPSS: 0.9% chance of exploitation in the next 30 days; higher than 58% of CVEs (scores of 2026-10-31)
CWE: CWE-20
Published: 2021-12-17
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

mattermost:mattermost_server

References

https://hackerone.com/reports/1253732
https://mattermost.com/security-updates/
https://hackerone.com/reports/1253732
https://mattermost.com/security-updates/

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