CVE-2017-18911 json
Mattermost Server has X.509 Improper Certificate Validation
published 2020-06-19 6 y ago modified 2026-06-17 4 mo ago also GHSA-m462-mqw4-2c8m , GO-2026-4464 , EUVD-2017-10001
- cvss
- 9.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 52%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- go github.com/mattermost/mattermost-server 3.6.7-rc1, 3.6.7-rc1+incompatible, 3.7.5, 3.7.5+incompatible, 3.8.2, 3.8.2+incompatible
- mattermost mattermost_server 3.6.7, 3.7.5, 3.8.2
- govulncheck-vulndb openSUSE Leap 15.6 0.0.20260226T182644-150000.1.149.1
suse advisories SUSE-SU-2026:0757-1
- govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
opensuse advisories openSUSE-SU-2026:21483-1
Exploit prediction
0.67% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| NVD | 2.0 | 6.4 | AV:N/AC:L/Au:N/C:P/I:P/A:N |
| GitHub | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/mattermost/mattermost-server | <3.6.7-rc1 >=3.7.0, <3.7.5 >=3.8.0, <3.8.2 <3.6.7-rc1+incompatible >=3.7.0+incompatible, <3.7.5+incompatible >=3.8.0+incompatible, <3.8.2+incompatible |
3.6.7-rc1 3.7.5 3.8.2 3.6.7-rc1+incompatible 3.7.5+incompatible 3.8.2+incompatible |
Classification
- Weakness
-
- CWE-295 Improper Certificate Validation
References
-
github.com
/mattermost/mattermost/commit/222bce0c5c1abb2f58c3a6de1fe8c5d3accffb21
web
-
github.com
/mattermost/mattermost/commit/691c18157025d4808b5b11de1d6de01050e54fa6
web
-
github.com
/mattermost/mattermost/commit/e9bb8cdfb4915067349a4840ab15ff941c4eb070
web
-
mattermost.com
/security-updates/
vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2017-18911
advisory
-
github.com
/mattermost/mattermost
package
-
mattermost.com
/security-updates
web
-
github.com
/advisories/GHSA-m462-mqw4-2c8m
advisory
Sources
- CVE List CVE-2017-18911
- GitHub Advisory GHSA-m462-mqw4-2c8m
- NVD CVE-2017-18911
- OSV GO-2026-4464
Fencer Vulns 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.