CVE-2017-18883

mediumpriority · track · 36EPSS 0.011 · 66 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.13% (66th) EPSS

CVSS 6.4 · medium

Is it mine?

10 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · osv · nvd

EPSS · scored 2026-10-28

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

Technical severity, 0–10. One row per scoring source.

9.1

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 6.4–9.1

v2.06.4mediumAV:N/AC:L/Au:N/C:P/I:P/A:Nprimary · NVD / NIST USexploitability 10 · impact 4.9

v3.19.1criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 5.2

v3.18.3highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-331USprimaryCWE-331US

affected products (10)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
mattermost mattermost server< 4.1.2nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost server4.2.0 → 4.2.1nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost server= 4.3.0nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Go github.com/mattermost/mattermost-server< 4.1.2osvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server< 4.1.2+incompatibleosvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server4.2.0-rc1 → 4.2.1osvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server4.2.0-rc1+incompatible → 4.2.1+incompatibleosvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server4.3.0-rc1 → 4.3.0osvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server4.3.0-rc1+incompatible → 4.3.0+incompatibleosvUSpkg:golang/github.com/mattermost/mattermost-server

advisories (2)

Vendor and ecosystem advisories describing this.

GHSA-w8cc-3h7q-jhc3Mattermost Server has low entropy for authorization data as an OAuth 2.0 Service Provider2022-05-24ghsa · osvUS
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.
GO-2025-4198Mattermost Server has low entropy for authorization data as an OAuth 2.0 Service Provider in github.com/mattermost/mattermost-server2025-12-08vendor · osvUS
Mattermost Server has low entropy for authorization data as an OAuth 2.0 Service Provider in github.com/mattermost/mattermost-server

also known as (5)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv nvd NVD CVE.org MITRE

published 2020-06-19modified 2026-06-17

related (185)

Related entries.

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+180 more

references (4)

External citations — patches, advisories, analysis.

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