CVE-2017-18911
Critical
Mattermost Server has X.509 Improper Certificate Validation in github.com/mattermost/mattermost-server
Mattermost Server has X.509 Improper Certificate Validation in github.com/mattermost/mattermost-server
Exploit probability
0.7%
Published
February 17, 2026
Required by
Not available
Last source change
February 19, 2026
02 / AFFECTED SOFTWARE
Affected packages
17 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
Open Source Vulnerabilities
CVE-2017-18911
View original source
An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. The X.509 certificate validation can be skipped for a TLS-based e-mail server.
Open Source Vulnerabilities
GHSA-m462-mqw4-2c8m
View original source
An issue was discovered in Mattermost Server before 3.8.2, 3.7.5, and 3.6.7. The X.509 certificate validation can be skipped for a TLS-based e-mail server.
Open Source Vulnerabilities
GO-2026-4464
View original source
Mattermost Server has X.509 Improper Certificate Validation in github.com/mattermost/mattermost-server
05 / REFERENCES
Further evidence
- https://mattermost.com/security-updates/
- https://github.com/mattermost/mattermost
- https://github.com/mattermost/mattermost/commit/222bce0c5c1abb2f58c3a6de1fe8c5d3accffb21
- https://github.com/mattermost/mattermost/commit/691c18157025d4808b5b11de1d6de01050e54fa6
- https://github.com/mattermost/mattermost/commit/e9bb8cdfb4915067349a4840ab15ff941c4eb070
- https://mattermost.com/security-updates
- https://nvd.nist.gov/vuln/detail/CVE-2017-18911
- https://github.com/advisories/GHSA-m462-mqw4-2c8m