CVE-2018-21259 json
An issue was discovered in Mattermost Server before 4.10.1, 4.9.4, and 4.8.2.
published 2020-06-19 6 y ago modified 2026-06-17 4 mo ago also EUVD-2018-13774
- cvss
- 5.3
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.1%
- EPSS 1.1% chance of exploitation in 30 days, percentile 65%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- mattermost mattermost_server 4.8.2, 4.9.4, 4.10.1
Exploit prediction
1.10% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P |
Classification
- Weakness
-
- CWE-20 Improper Input Validation
References
-
mattermost.com
/security-updates/
vendor-advisory
Sources
- CVE List CVE-2018-21259
- NVD CVE-2018-21259
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.