9.1

CVE-2017-18883: mattermost mattermost_server Insufficient Entropy

CVSS: 9.1v3.1CriticalModified
AliasesGHSA-w8cc-3h7q-jhc3GO-2025-4198
Published 19-06-2020Last modified 05-08-2024
Open JSON

Vulnerability summary

CVE-2017-18883 is a critical (CVSS 9.1) Insufficient Entropy vulnerability in mattermost mattermost_server. EPSS estimates a 1.13% chance of exploitation in the next 30 days, higher than 65.9% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.1/10
010
Critical · v3.1 (NVD)
EPSS score
1.13%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2026:21483-1SUSE-SU-2025:4395-1

Timeline

  1. 19-06-2020
    PublishedVulnerability first disclosed.
  2. 05-08-2024
    Last modifiedVulnerability information updated.

Description

An issue was discovered in Mattermost Server before 4.3.0, 4.2.1, and 4.1.2, when serving as an OAuth 2.0 Service Provider. There is low entropy for authorization data.

CVSS metrics

3 scores · 2 sources · 3 versions

EPSS trend

Probability

1.13%

Chance of exploitation in the next 30 days

Percentile

66%

Versus all other CVEs

30-day change

+0.01 pp

From 1.13% on 18-09-2026

18-09-202618-10-2026
EPSS score
1.13%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Github.com/mattermost1 product
  • mattermost-server< 4.1.2 | ≥ 4.2.0-rc1, < 4.2.1 | ≥ 4.3.0-rc1, < 4.3.0 | ≥ 4.3.0-rc1+incompatible, < 4.3.0+incompatible
Mattermost1 product
  • mattermost_server< 4.1.2 | ≥ 4.2.0, < 4.2.1 | 4.3.0:rc1 | 4.3.0:rc2 | 4.3.0:rc3 | 4.3.0:rc4

2 vendors · 2 products

References

5 links