CVE-2018-21258

FAUCET Score

CVE-2018-21258 is a denial-of-service vulnerability affecting Mattermost Server versions prior to 5.1, allowing unauthenticated attackers to disrupt service. With a CVSS score of 7.5 (High), it can be exploited remotely with low complexity, leading to a complete loss of availability. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

Vendor	Product	Version(s)	CPE
		< 5.1.0CPE matchmatch criteria	cpe:2.3:a:mattermost:mattermost_server::::::::

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

Exploitability Score

3.9

Impact Score

3.6

CvssVersion

3.1

Exploit Intelligence

EPSS Score

1.16%

Probability of exploitation in next 30 days

EPSS Percentile

63.7%

Percentile rank of EPSS score among Peer Group

As of 2026-07-27

Model: v2026.06.15

This CVE's current EPSS score of 0.0115 is in the 42nd percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

gopatch availablevia ghsa

Product: github.com/mattermost/mattermost-serverFixed in: 5.1.0

Vendor Advisories (1)

goGHSA-5mh6-p63g-3mv5high

Mattermost Server is vulnerable to a Denial of Service attack through `invite_people` command

May 24, 2022

References

mattermost.com / security-updates

Vendor Advisory