CVE-2024-39839

mediumpriority · track · 17EPSS 0.003 · 27 %ileDEEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.34% (27th) EPSS

CVSS 4.3 · medium

Is it mine?

24 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · osv · cert_bund

EPSS · scored 2026-10-27

Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the local server as long as the user hadn't been synced before.

cvss

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

4.3

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 1.4

v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:Nsecondary · ENISA EU

v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:Nsecondary · responsibledisclosure@mattermost.comexploitability 2.8 · impact 1.4

v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:Nsecondary · OSV

v3.14mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-284USCWE-284US

affected products (24)

Products and version ranges known to be affected.

Mattermost Mattermost Pluginsall versionscert_bundDEcpe:/a:mattermost:mattermost_server:plugins
Mattermost Mattermost≤ 9.9.0enisa_euvdEU
Mattermost Mattermost≤ 9.5.0 ≤9.5.6enisa_euvdEU
Mattermost Mattermost≤ 9.7.0 ≤9.7.5enisa_euvdEU
Mattermost Mattermost≤ 9.8.0 ≤9.8.1enisa_euvdEU
mattermost mattermost server9.5.0 → 9.5.7nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost server9.7.0 → 9.7.6nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost server9.8.0 → 9.8.2nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
mattermost mattermost server= 9.9.0nvdUScpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Bitnami mattermost9.5.0 → 9.5.7osvUSpkg:bitnami/mattermost
Bitnami mattermost9.7.0 → 9.7.6osvUSpkg:bitnami/mattermost
Bitnami mattermost9.8.0 → 9.8.2osvUSpkg:bitnami/mattermost
Bitnami mattermost= 9.9.0osvUSpkg:bitnami/mattermost
Go github.com/mattermost/mattermost-server9.5.0+incompatible → 9.5.7+incompatibleosvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server9.7.0+incompatible → 9.7.6+incompatibleosvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server9.8.0+incompatible → 9.8.2+incompatibleosvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server9.9.0+incompatible → 9.9.1+incompatibleosvUSpkg:golang/github.com/mattermost/mattermost-server
Go github.com/mattermost/mattermost-server/v5all versionsosvUSpkg:golang/github.com/mattermost/mattermost-server/v5
Go github.com/mattermost/mattermost-server/v6all versionsosvUSpkg:golang/github.com/mattermost/mattermost-server/v6
Go github.com/mattermost/mattermost/server/v8all versionsosvUSpkg:golang/github.com/mattermost/mattermost/server/v8

showing 20 of 24

advisories (4)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2024-1715Mattermost: Mehrere Schwachstellen ermöglichen nicht spezifizierten AngriffDeutsch2024-07-25csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Mattermost ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.
GHSA-vg6q-84p8-qvqhMattermost allows a user on a remote to set their remote username prop to an arbitrary string2024-08-01ghsa · osvUS
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the local server as long as the user hadn't been synced before.
BIT-mattermost-2024-398392024-09-05vendor · osvUS
Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5, 9.8.x <= 9.8.1 fail to disallow users to set their own remote username, when shared channels were enabled, which allows a user on a remote to set their remote username prop to an arbitrary string, which would be then synced to the local server as long as the user hadn't been synced before.
GO-2024-3024Mattermost allows a user on a remote to set their remote username prop to an arbitrary string in github.com/mattermost/mattermost-server2024-08-06vendor · osvUS
Mattermost allows a user on a remote to set their remote username prop to an arbitrary string in github.com/mattermost/mattermost-server

also known as (6)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv cert_bund nvd NVD CVE.org MITRE

published 2024-08-01modified 2026-06-17

references (4)

External citations — patches, advisories, analysis.

scry

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